Do Right Handed Hitters have Less Severe Platoon Splits?

[stringer bell]

In another thread, I speculated that right handed hitters have less severe platoon splits. I suppose there are stats somewhere that either validate my thought or or refute it. 

I checked the platoon splits of top Twins hitters and found that right handed hitter splits were less severe than for left handed hitters. I checked the top four left handed hitters in Twins' history and the top three right handed hitters in Twins' history plus Paul Molitor and checked their career OPS splits. All eight hitters hit better with the platoon advantage. Of the top lefties, only Rod Carew had a disparity of less than 100 OPS points and Tony Oliva had a spread of .200 (.890 vs. RH pitchers, .690 vs. LH pitchers). 

All time great right handed hitters didn't have splits as great as the lefties. Kirby had a disparity of .094 (largest) while Harmon Killebrew had the smallest--.058. 

If somebody has more information on this topic, I'd like to see it. It might explain some of Rocco's willingness to pinch hit for Wallner, Kirilloff and Julien early in their careers. 

[IndianaTwin]

Here's one season's worth (2023). I don't know whether these differences are statistically significant, but righties batting against righties did .017 better than lefties against lefties. And the platoon advantage is real -- righties against lefties and lefties against righties each did better than people batting against their same handedness. 

Intuitively, your hypothesis makes some sense. Righties have more opportunities against righties in their developmental years than lefties do against lefties. 

[Riverbrian]

Thanks String... Oh Boy... Do I love this topic. 

As much as I complain about the extreme platooning being done by Rocco. At the same time... I also recognize that Rocco has consistent statistical justification for it. 

The Numbers for 2023 posted by IndyTwin are large sample numbers that are repeatable year after year. The left handed hitter consistently has the harder time against the southpaw. 

I say it often... I'm not anti-platoon. I get it and it isn't just the hitters splits. You also have to factor in the pitchers splits so the split margin is larger when you combine them both together.  

However... no matter what the collective says. IMO you can't just follow this data without question like Rocco seems to. 

1. We are still talking about individuals and not the collective in each individual matchup. A good left handed hitter is still a good hitter even if he doesn't hit lefties as well as righties and the actual advantage at a per AB basis is probably miniscule. Julien's home run yesterday didn't prove anything because it's a small sample... just like Julien striking out against a lefty doesn't prove anything in such a small sample. But... Julien is a good hitter and probably more likely to go deep against a lefty than Margot is against a lefty... you got keep putting him up there against the southpaws for a couple of years before you decide... OK... He's Joc Pederson.      

2. We are still talking about development. Exposure is necessary for improvement. Don't cement him into this lesser role for a marginal increase in odds of success. When you have a young players with 4, 5, 6 years of control... they can become so much more than what they currently are. Don't doom your talented lefties to this for a possible marginal advantage in one AB in one game.   

3. And... this is often overlooked and it shouldn't be. Players get hurt... team context can change on a dime. Not letting Julien or Kirilloff face left handers in April, May, June and July is going to make your team vulnerable when Correa and Lewis both go down in late September and that almost happened last year. We didn't know the status of Correa and Lewis on the eve of the playoffs. If you lose a couple of key right handed hitters at the wrong time and you will be forced to turn Julien against Framber Valdez in the playoffs. Sorry... wouldn't let you face Angel Zerpa during the regular season but we need you to come up big against Framber now. Yeah... I know... we can always pull a Jordan Luplow or Kyle Garlick off the waiver wire and win the world series. 😄  

4. Speaking of Luplow and Garlick. Perhaps an even more important point. In order to set up 3 platoons for Julien, Kirilloff and Wallner. You have to sign 3 lesser players to hold down the short side. Luplow, Garlick types... Margot for example. You are not going to sign JD Martinez for a short side platoon. 3 lesser players on your roster makes it impossible to have the decent depth necessary to cover for injuries that are going to happen or unforeseen bad performance that happens ever year. Last year Solano worked out decently but he wasn't brought on to play as much as he did. He had to play because of injuries. You actually sacrifice talent to maintain the platoon. Just go get talent instead is my opinion.   

In a nutshell... The collective stats absolutely support Rocco's extreme sheltering of lefties against lefties but I still say the 4 points above negate what could be a tiny margin statistical advantage at the individual AB level.   

[Linus]

36 minutes ago, Riverbrian said:

Thanks String... Oh Boy... Do I love this topic. 

As much as I complain about the extreme platooning being done by Rocco. At the same time... I also recognize that Rocco has consistent statistical justification for it. 

The Numbers for 2023 posted by IndyTwin are large sample numbers that are repeatable year after year. The left handed hitter consistently has the harder time against the southpaw. 

I say it often... I'm not anti-platoon. I get it and it isn't just the hitters splits. You also have to factor in the pitchers splits so the split margin is larger when you combine them both together.  

However... no matter what the collective says. IMO you can't just follow this data without question like Rocco seems to. 

1. We are still talking about individuals and not the collective in each individual matchup. A good left handed hitter is still a good hitter even if he doesn't hit lefties as well as righties and the actual advantage at a per AB basis is probably miniscule. Julien's home run yesterday didn't prove anything because it's a small sample... just like Julien striking out against a lefty doesn't prove anything in such a small sample. But... Julien is a good hitter and probably more likely to go deep against a lefty than Margot is against a lefty... you got keep putting him up there against the southpaws for a couple of years before you decide... OK... He's Joc Pederson.      

2. We are still talking about development. Exposure is necessary for improvement. Don't cement him into this lesser role for a marginal increase in odds of success. When you have a young players with 4, 5, 6 years of control... they can become so much more than what they currently are. Don't doom your talented lefties to this for possible marginal improvement.  

3. And... this is often overlooked and it shouldn't be. Players get hurt... team context can change on a dime. Not letting Julien or Kirilloff face left handers in April, May, June and July is going to make your team vulnerable when Correa and Lewis both go down in late September and that almost happened last year. We didn't know the status of Correa and Lewis on the eve of the playoffs. If you lose a couple of key right handed hitters at the wrong time and you will be forced to turn Julien against Framber Valdez in the playoffs. Sorry... wouldn't let you face Angel Zerpa during the regular season but we need you to come up big against Framber now. Yeah... I know... we can always pull a Jordan Luplow or Kyle Garlick off the waiver wire and win the world series. 😄  

In a nutshell... The collective stats absolutely support Rocco's extreme sheltering of lefties against lefties but I still say the 3 points above negate what could be a tiny margin statistical advantage at the individual AB level.   

I agree with point #3 emphatically. However the rest of the stats are pretty damning. Gleeman wrote a very informative article on this a few weeks ago. Essentially all the best left handed hitters in Twins history had a 20% decline one OPS against left handed pitching. Only Carew hit lefties and we are talking about some great hitters like Olivia Morneau etc.  This wasn’t limited to Twins hitters either. Across league history this was the case. From memory another poster looked up Juliens minor league numbers against lefties and it was pretty ugly and the sample was pretty large. I hope Julien Wallner and Kiriloff learn to hit lefties at the big league level and want them to get a fair chance but the stats support Rocco big time on this. 

[Riverbrian]

13 minutes ago, Linus said:

I agree with point #3 emphatically. However the rest of the stats are pretty damning. Gleeman wrote a very informative article on this a few weeks ago. Essentially all the best left handed hitters in Twins history had a 20% decline one OPS against left handed pitching. Only Carew hit lefties and we are talking about some great hitters like Olivia Morneau etc.  This wasn’t limited to Twins hitters either. Across league history this was the case. From memory another poster looked up Juliens minor league numbers against lefties and it was pretty ugly and the sample was pretty large. I hope Julien Wallner and Kiriloff learn to hit lefties at the big league level and want them to get a fair chance but the stats support Rocco big time on this. 

Yeah... I won't argue the research.

Tony Oliva had a career .890 against RH and .690 against LH. 

Justin Morneau was .886 against RH and .710 against LH. 

Joe Mauer was .868 against RH and .740 against LH. 

It's why I'm not anti-platoon. I get it. 

Moderation is what I'm asking. My doctor told me that wine is good for me. On my next visit... my doctor told me that drinking 5 bottles a night and throwing up on the cat is not good for me. 

 

[CCHOF5yearstoolate]

2 hours ago, IndianaTwin said:

Here's one season's worth (2023). I don't know whether these differences are statistically significant, but righties batting against righties did .017 better than lefties against lefties. And the platoon advantage is real -- righties against lefties and lefties against righties each did better than people batting against their same handedness. 

Intuitively, your hypothesis makes some sense. Righties have more opportunities against righties in their developmental years than lefties do against lefties. 

Just learned Fangraphs can actually do a huge amount of data just for this.

All LHB vs. LHP in FG's database with pitcher/batter handedness (link)

.241/.310/.372 for a .682 OPS compared to .261./336/.424 and a .760 OPS against RHP (78 point dropoff vs LHP)

 

All RHB vs RHP in the database (link)

.252/.313/.404 for a .717 OPS compared to .264/.333/.429 and a .762 OPS against LHP (45 point dropoff vs RHP)

So lefties experience a 73% larger dropoff when facing same-handed pitching. 

[Linus]

47 minutes ago, Riverbrian said:

Yeah... I won't argue the research.

Tony Oliva had a career .890 against RH and .690 against LH. 

Justin Morneau was .886 against RH and .710 against LH. 

Joe Mauer was .868 against RH and .740 against LH. 

It's why I'm not anti-platoon. I get it. 

Moderation is what I'm asking. My doctor told me that wine is good for me. On my next visit... my doctor told me that drinking 5 bottles a night and throwing up on the cat is not good for me. 

 

Yep - that’s why point number 3 you made is so valid. They will have to face a lefty at some point whether they like it or not. 

[IndianaTwin]

33 minutes ago, CCHOF5yearstoolate said:

Just learned Fangraphs can actually do a huge amount of data just for this.

All LHB vs. LHP in FG's database with pitcher/batter handedness (link)

.241/.310/.372 for a .682 OPS compared to .261./336/.424 and a .760 OPS against RHP (78 point dropoff vs LHP)

 

All RHB vs RHP in the database (link)

.252/.313/.404 for a .717 OPS compared to .264/.333/.429 and a .762 OPS against LHP (45 point dropoff vs RHP)

So lefties experience a 73% larger dropoff when facing same-handed pitching. 

I'll give you a "like" for the final sentence alone. I hate it when people subtract (i.e., comparing 78 percentage points to 45 percentage points and calling the first 33 percent larger), rather than doing the (y-x)/x. If their math is off on that, it makes me wonder where else their math is wrong. 

[ashbury]

52 minutes ago, Riverbrian said:

my doctor told me that drinking 5 bottles a night and throwing up on the cat is not good for me.

You should seek out a second medical opinion.  Ask your cat's vet what the research is on the harm to the cat.

[ashbury]

3 hours ago, IndianaTwin said:

Here's one season's worth (2023). I don't know whether these differences are statistically significant, but righties batting against righties did .017 better than lefties against lefties. And the platoon advantage is real -- righties against lefties and lefties against righties each did better than people batting against their same handedness. 

Intuitively, your hypothesis makes some sense. Righties have more opportunities against righties in their developmental years than lefties do against lefties. 

When I look at league-wide splits and they are as narrow as that, it makes me wonder if putting up with a guy that has a high platoon split is even worth the bother on average.  And it especially makes me question the Twins' apparent strategy to load up on left-handed hitters - the upside doesn't look as high as I thought.

[Riverbrian]

29 minutes ago, ashbury said:

When I look at league-wide splits and they are as narrow as that, it makes me wonder if putting up with a guy that has a high platoon split is even worth the bother on average.  And it especially makes me question the Twins' apparent strategy to load up on left-handed hitters - the upside doesn't look as high as I thought.

I agree

However... 75% of the arms are right handed. So... if you are really playing the numbers... More lefties. 

 

[Parfigliano]

4 hours ago, IndianaTwin said:

Here's one season's worth (2023). I don't know whether these differences are statistically significant, but righties batting against righties did .017 better than lefties against lefties. And the platoon advantage is real -- righties against lefties and lefties against righties each did better than people batting against their same handedness. 

Intuitively, your hypothesis makes some sense. Righties have more opportunities against righties in their developmental years than lefties do against lefties. 

Good point

[USAFChief]

A couple thoughts:

1. platoon advantage is real, has been since the first baseball game was played. It's simply easier to hit pitches breaking toward you than breaking away. I also believe it's easier for humans vision to pick up the ball from opposite handed pitchers. 

2. I think right handed hitters suffer less from the platoon disadvantage because they see way more RH pitching growing up than LH hitters see LH pitching. They get more practice. And the Darwin theory starts to eliminate right handed hitters whi can't hit RH pitching long before they progress to higher levels. 

3. I often post "reverse splits are a mirage." It's sort of a joke, but mostly not. I'm very skeptical that true reverse splits are actually true, and not a statistical quirk that will correct itself over time. 

As for Rocco:

I don't have a problem with using platoons. It's a simple and financially feasible way to squeeze some extra offense out of your roster. And as we can see, most LH bats never turn into good LH hitters against LH pitching. If Tony Oliva, Joe Mauer and Justin Morneau suffered against LHers, do we really need to give Wallner or Julien hundreds of ABs just to learn what we already knew?

My problem is PHing a RHed bat for a 1 AB platoon advantage in early or middle innings. That spot in the order is coming around again, maybe more than once. And there's a huge chance it will be against RHed pitching. You're going to be giving up the platoon advantage in at least one of those ABs. I'd rather let Julien face a lefty in the 5th and RH relievers from then on, over getting Farmer an AB against that lefty in the 5th, but then face those same RH relievers from then on. I truly believe teams have been intentionally putting Rocco in position to remove his best hitters.

 

[Riverbrian]

9 minutes ago, USAFChief said:

A couple thoughts:

1. platoon advantage is real, has been since the first baseball game was played. It's simply easier to hit pitches breaking toward you than breaking away. I also believe it's easier for humans vision to pick up the ball from opposite handed pitchers. 

2. I think right handed hitters suffer less from the platoon disadvantage because they see way more RH pitching growing up than LH hitters see LH pitching. They get more practice. And the Darwin theory starts to eliminate right handed hitters whi can't hit RH pitching long before they progress to higher levels. 

3. I often post "reverse splits are a mirage." It's sort of a joke, but mostly not. I'm very skeptical that true reverse splits are actually true, and not a statistical quirk that will correct itself over time. 

As for Rocco:

I don't have a problem with using platoons. It's a simple and financially feasible way to squeeze some extra offense out of your roster. And as we can see, most LH bats never turn into good LH hitters against LH pitching. If Tony Oliva, Joe Mauer and Justin Morneau suffered against LHers, do we really need to give Wallner or Julien hundreds of ABs just to learn what we already knew?

My problem is PHing a RHed bat for a 1 AB platoon advantage in early or middle innings. That spot in the order is coming around again, maybe more than once. And there's a huge chance it will be against RHed pitching. You're going to be giving up the platoon advantage in at least one of those ABs. I'd rather let Julien face a lefty in the 5th and RH relievers from then on, over getting Farmer an AB against that lefty in the 5th, but then face those same RH relievers from then on. I truly believe teams have been intentionally putting Rocco in position to remove his best hitters.

 

Agree with everything you wrote. 

However... IMO... Yes... you still have to give them AB's. 

Because of Martha and the Vandella's. 

[USAFChief]

15 minutes ago, Riverbrian said:

Agree with everything you wrote. 

However... 

One of the greatest things about TD is Riverbrian. 

Never change, my friend. 

[Riverbrian]

2 minutes ago, USAFChief said:

One of the greatest things about TD is Riverbrian. 

Never change, my friend. 

Ten Years After

But I don't know what to do. 

[DocBauer]

OK, a weird reference, but in football, LH QB and LH punters have a different spin on their balls. And I've always wondered if LHP in baseball don't have a different spin to their balls. Does that make it even more difficult for LH hitters?

The reason I say this is CLEARLY a RH batter sees RHP 75-80% of the time. LH batters also see RHP 75-80% of the time. So clearly there is a familiarity with all hitters facing RHP. If you're a RH hitter who can't hit RHP, you aren't going to have much of a future. Reserve, platoon type of journeyman at best.

@usafchief is correct that it has to be easier to pick up a ball spinning towards you rather than breaking away. Hence, RH hitters are usually better against LHP, and LHP are usually better against RHP. Pretty basic logic, right? So again, a RH hitter who can't hit RHP doesn't have much of a career. And the lack of a LH batter facing LHP in their LIFE makes the adjustment much harder. Again, pretty basic stuff. 

But part of me has always wondered if it's not just facing so fewer LHP in their careers...balls breaking differently...but I wonder if the change in spin doesn't also add to the rather large discrepancy? Meaning LH hitters have 2 different obstacles to overcome, side and spin both.

All that being said:

1] Platoons make sense. But you can't platoon all 9 spots in the order. SOMEONE or a couple someone's have to be a LH bat against a LHP in every single game.

2] It's a mistake to PH too early in games because more than likely, that PH is going to face a RH reliever later in the game. And you just CAN'T pull your best LH bats too early with the rest of the game. Unfortunately, we've seen that happen too often at times.

3] Even though platoons make sense, if your top LH hitter, possibly with power, drops a 100 or more points in OPS from...say 850 to 720...against a LHP, is he really that much worse than a RH hitter with limited or little power but an OPS of .800?

4] Until you actually allow your LH hitters to actually play against LHP, how will you ever know if they can be OK, or terrible? Since you're always going to have some LH bats in the lineup no matter what, give them time to see if they can adapt and potentially be "decent". Or...not.

 

[DJL44]

1 hour ago, DocBauer said:

4] Until you actually allow your LH hitters to actually play against LHP, how will you ever know if they can be OK, or terrible? Since you're always going to have some LH bats in the lineup no matter what, give them time to see if they can adapt and potentially be "decent". Or...not.

If a lefthanded batter can't hit lefty pitching in practice they won't be able to hit it in games. They get a lot more reps in practice.

[stringer bell]

I mostly agree that players shouldn’t be pinch-hit for in the middle innings, but I’ll be a bit of a devil’s advocate here—sometimes the game situation is in the middle innings. Getting a solid right handed hitter to face a lefty who might be the seventh or eighth best bullpen arm might be the best opportunity to win a game. 

This year, as last, the right handed options are more veteran, lower upside and better defenders than the hitters they would replace. I hope that Kirilloff and Julien prove they can handle lefties well enough that they aren’t pulled. I have less hope for Wallner. 

[Linus]

7 minutes ago, stringer bell said:

I mostly agree that players shouldn’t be pinch-hit for in the middle innings, but I’ll be a bit of a devil’s advocate here—sometimes the game situation is in the middle innings. Getting a solid right handed hitter to face a lefty who might be the seventh or eighth best bullpen arm might be the best opportunity to win a game. 

This year, as last, the right handed options are more veteran, lower upside and better defenders than the hitters they would replace. I hope that Kirilloff and Julien prove they can handle lefties well enough that they aren’t pulled. I have less hope for Wallner. 

Yea I think the idea that drives some of us nuts is that sometimes the best chance to break a game open is in the fifth inning. No sense in saving the platoon advantage for a later opportunity that never comes. If there are ducks on the pond then shoot your wad. 

[Parfigliano]

15 minutes ago, stringer bell said:

I mostly agree that players shouldn’t be pinch-hit for in the middle innings, but I’ll be a bit of a devil’s advocate here—sometimes the game situation is in the middle innings. Getting a solid right handed hitter to face a lefty who might be the seventh or eighth best bullpen arm might be the best opportunity to win a game. 

This year, as last, the right handed options are more veteran, lower upside and better defenders than the hitters they would replace. I hope that Kirilloff and Julien prove they can handle lefties well enough that they aren’t pulled. I have less hope for Wallner. 

How do the LHH get a chance to show they can hit LHP when Rocco takes the chance away?

Chess players...when Rocco PH for Julien--Wallner against a LHP he effectively sacrifices a piece for a pawn.

[USAFChief]

40 minutes ago, DJL44 said:

If a lefthanded batter can't hit lefty pitching in practice they won't be able to hit it in games. They get a lot more reps in practice.

It's tough to find enough LH pitchers to even give LH hitters much live BP. You can set up pitching machines to mimic LH breaking balls, but IMO pitching machines are only so useful.

[USAFChief]

44 minutes ago, stringer bell said:

I mostly agree that players shouldn’t be pinch-hit for in the middle innings, but I’ll be a bit of a devil’s advocate here—sometimes the game situation is in the middle innings. Getting a solid right handed hitter to face a lefty who might be the seventh or eighth best bullpen arm might be the best opportunity to win a game. 

This year, as last, the right handed options are more veteran, lower upside and better defenders than the hitters they would replace. I hope that Kirilloff and Julien prove they can handle lefties well enough that they aren’t pulled. I have less hope for Wallner. 

But Rocco has been doing the middle inning PH thing for years. SItuation has little or nothing to do with it. He PHs with 2 out and nobody on. I recall you calling him out on it last year,  for example.

[Riverbrian]

8 hours ago, stringer bell said:

I mostly agree that players shouldn’t be pinch-hit for in the middle innings, but I’ll be a bit of a devil’s advocate here—sometimes the game situation is in the middle innings. Getting a solid right handed hitter to face a lefty who might be the seventh or eighth best bullpen arm might be the best opportunity to win a game. 

 

 

For example... the bases are loaded in the 5th inning. Manager brings in a left handed pitcher to face Kirilloff. Bringing in Margot (So he can bunt?) makes some sense. Swapping a .292 OBP for a .342 OBP makes some sense. Swapping a .637 OPS for a .766 makes some sense.

However, please consider that there is still game to go. More innings where runs can be produced are still scheduled for competition. Margot with his .662 OPS against right handers will be facing right handers the rest of the way as the innings of opportunity become less and less ending potentially with the right handed closer in the 9th when there are no innings left. 

The problem is though while I can understand the pinch hit in a key situation. Rocco doesn't do that. He pushes the button with 4 run leads, 4 run deficits, he pulls our young lefties with two outs and nobody on. He yanked Julien before he got a chance to bat last year.

It's auto pilot... Southpaw into the game... Julien, Kirilloff and Wallner out. 

We are making it much harder for Julien, Kirilloff and Wallner to sign that big free agent contract in the future so Margot can be the hero. We are minimizing the trade value of Julien, Kirilloff and Wallner so Margot can be the hero. We are paying millions (that we don't have) to Margot to make it harder for Julien, Kirilloff and Wallner to become more valuable. 

But,... for that one AB. We went from a 29% chance of reaching base to a 34% chance. Add 5 green  balls to the 100 ball raffle drum. 

 

[Riverbrian]

I'd love to hear some thoughts on this. 

There are other splits, other data points for match up consideration. How batters do against fastballs, breaking pitches, change ups for example. There has to be a lot of data produced with all of the analysts being employed and with all that data... lineup construction seemingly hasn't advanced past the right hander/left hander thing. Like they are only data points that matter. 

[JD-TWINS]

16 hours ago, stringer bell said:

In another thread, I speculated that right handed hitters have less severe platoon splits. I suppose there are stats somewhere that either validate my thought or or refute it. 

I checked the platoon splits of top Twins hitters and found that right handed hitter splits were less severe than for left handed hitters. I checked the top four left handed hitters in Twins' history and the top three right handed hitters in Twins' history plus Paul Molitor and checked their career OPS splits. All eight hitters hit better with the platoon advantage. Of the top lefties, only Rod Carew had a disparity of less than 100 OPS points and Tony Oliva had a spread of .200 (.890 vs. RH pitchers, .690 vs. LH pitchers). 

All time great right handed hitters didn't have splits as great as the lefties. Kirby had a disparity of .094 (largest) while Harmon Killebrew had the smallest--.058. 

If somebody has more information on this topic, I'd like to see it. It might explain some of Rocco's willingness to pinch hit for Wallner, Kirilloff and Julien early in their careers. 

There was a piece (maybe in Athletic? - Twins specific) maybe 5-6 weeks ago showing all “good” Twins that batted left handed. Maybe a dozen guys? Koskie - Kubel - Oliva - Carew - Morneau - Hrbek - Mauer and another 4-5 guys. Bottom line is it showed left handed hitters (article supported logic of platooning for lefties) had pretty big drops v. LH pitching. Oliva having a .690 OPS was telling! Carew was lower but still above average. ALL guys were lower v. LH pitching, some everyday guys were pretty significant drops.

The premise was that guys see waaay more RH pitching while kids & learning & as young men and then through their careers. RH hitters get used to seeing RH pitching and are in a sink or swim situation their whole lives v. RH pitching. LH hitters see predominantly RH pitching and then in the Show the lefties they see more of, are professionals. Poor results.

Wallner - Julien - name anyone batting left handed……..probably are never, regardless of fans just wanting “to give them a chance”, going to be effective or nearly as effective v. LH pitching. The platoon makes sense! ………similar stuff for RH hitters but more accepted maybe? 

[DJL44]

8 hours ago, USAFChief said:

It's tough to find enough LH pitchers to even give LH hitters much live BP. You can set up pitching machines to mimic LH breaking balls, but IMO pitching machines are only so useful.

That's a problem. If they can't practice batting against lefties they'll never get better. They pay a guy to be the bullpen catcher. There have to be some unemployed lefthanded pitchers they can hire to throw batting practice.

[wabene]

They left in Julien and he smacks his first homer against a southpaw. More of this please. After a rough start Julien is heating up, do not make him a part time player. 

[chpettit19]

9 hours ago, USAFChief said:

It's tough to find enough LH pitchers to even give LH hitters much live BP. You can set up pitching machines to mimic LH breaking balls, but IMO pitching machines are only so useful.

For Julien's sake, I hope you're wrong on this. He spent the offseason using the Trajekt machine to learn to hit lefties. The machines these days are pretty fancy. That machine has a video screen that shows a pitcher winding up and throwing the ball from any release point, and the ability to mimic the spin of actual MLB pitches. It's pretty impressive stuff, and I'd think it could be quite effective in allowing lefties to get as many reps as they want/need against "lefties" to improve their abilities.

[CCHOF5yearstoolate]

11 hours ago, DocBauer said:

But part of me has always wondered if it's not just facing so fewer LHP in their careers...balls breaking differently...but I wonder if the change in spin doesn't also add to the rather large discrepancy? Meaning LH hitters have 2 different obstacles to overcome, side and spin both.

I'm no expert, but I also think there is a difference in spin/movement from LHP. Think of the big breaking pitches, Rich Hill's curveball or Chris Sale's back foot slider - what RHP throws a pitch like that? You could maybe say Jose Berrios throws a similar curveball - but that's been defined as a slurve. And even though MLB has done reclassification of many sliders to be sweepers, Chris Sale still throws a slider by their classification.

You can also look at the spin profiles of a lefty vs a righty. I'll note here that I didn't do any kind of deep dive or compare their mechanics so this could just be confirmation bias after finding the first 2 pitchers with similar offerings.

Look at the difference in the movement of each of Max Fried's pitches compared to Pablo's. Even if you mirror these graphics there's a few 'hours' of movement difference between both.