On Eiberson Castellano and the Role No One Player Can Fill

[Tom Froemming]

It's not enough. Few solid hurlers left, but it's not enough. Few pitchers that'll really step, but it's not enough.

Image courtesy of © Chris Tilley-Imagn Images

Managers do their best with disaster prep, but when it comes to bullpen management, there’s no way to prepare for everything. There are going to be games where a starter can’t deliver innings. There will be times when a bullpen is stretched thin. There are extra-inning marathons, doubleheaders and mid-game weather delays that throw monkey wrenches into the works.

When worse comes to worst, the mop-up man saves the day. Well, it would be more accurate to say he saves the other arms. A mop-up man doesn’t often help his team win; he’s there to eat innings. In that sense, it’s easy to think anybody can be a mop-up man. To some degree, I suppose that’s true. If you're down by enough runs, even a position player can cover mop-up duty on the mound.

The challenge is less finding someone to fill the mop-up role, and more what to do with him after he’s provided his service. The options are usually either to basically play shorthanded in the bullpen for a few days or demote your mop-up man to call up a fresh arm. That being the case, it’s nearly impossible to have a mop-up man you can’t send down to the minors. This, of course, creates a big problem for the future of Eiberson Castellano as a Twin.

Castellano is a talented pitcher. He won the Phillies' Minor League Pitcher of the Year honors in 2024, before being selected by the Twins with the ninth pick in the Rule 5 draft. He must stick on the Twins' active roster, or be waived, and if he clears waivers, he has to be offered back to Philadelphia. Currently, mop-up duty is the only role he currently looks suited for in the majors.

So far this spring, Castellano has been awful more times than he’s been awesome. As he's a 23-year-old who hasn’t pitched above Double A, it should be little surprise that Castellano has run into some trouble. After a rough outing on Tuesday, his ERA is up to 9.35, to go with a 1.85 WHIP over 8 2/3 innings this spring. Still, with a four-seam fastball touching 97 mph a useful curveball and a changeup with a chance to be average, Castellano has the foundation of a big-league arsenal. He’s struck out 12 of the 44 batters he’s faced this spring (27.3%), despite struggling with his control and command.

The team has also made sure to give him some tough assignments, the better to evaluate him against high-level competition. By Baseball Reference's Opponent Quality metric (an important tool to account for the uneven levels of opponents a player sees in spring ball), Castellano's 7.5 is the median figure among the 19 Twins who have thrown at least five innings this year. That number signifies something between Double-A and Triple-A talent, so it's pushing him beyond his comfort zone. Jhoan Durán (7.4), Jorge Alcalá (7.1) and Chris Paddack (6.8) have all faced a lower level of competition than Castellano. 

This is exactly the kind of arm you’d love to be able to stash for a year and steal away from another org. It’s just not that easy. There are enough low-leverage opportunities; the challenge comes from the bigger picture of bullpen management. It's easy to say "just stick him in a mop-up role." But here's the thing: No single pitcher can cover that role for an entire season.

There are times when it’s necessary to churn and burn. Last season, there were 14 instances where a Twins reliever had to record more than six outs, meaning that pitcher was unavailable for the next day or three. In those situations, teams often show their appreciation for the effort by demoting that pitcher. 

One example from last year is when Pablo López could only cover four innings against the Tigers on April 12. That doesn’t sound like much of a doomsday scenario, but the Twins had a doubleheader the next day. The first game went 12 innings. They had no time to take a breath, as their next game was the following afternoon.

Over those two days, Cole Sands covered 2 1/3 innings in an outing, while both Michael Tonkin and Alcalá had two-inning appearances. Additionally, Kody Funderburk and Jay Jackson worked back-to-back days. That’s five of eight bullpen spots who were likely going to be unavailable the next day (if not multiple days). Tonkin was the victim in that instance. The Twins had just acquired him from the Mets on April 9, but they designated him for assignment on the April 13 because they needed a fresh arm.

There were other disaster scenarios last season, but we typically think of them coming later in the year. The early-season schedule includes more days off than usual, to accommodate potential weather postponements, but it doesn’t completely prevent bullpen management nightmares from popping up as early as mid-April.

I suppose it’s possible to lock Castellano into a low-leverage spot and view a few of the other bullpen arms as the mop-up, churn-and-burn guys. Alcalá, Louis Varland, Justin Topa and Funderburk all still have options, so they could be up-and-down guys, yo-yo'ing between Minneapolis and St. Paul. There are also a host of arms not currently on the 40-man roster who could be used in a pinch, as we see every year. Those names include Huascar Ynoa, Randy Dobnak, Scott Blewett, Ryan Jensen and Anthony Misiewicz, among others.

It seems like the amount of gymnastics it would require to keep Castellano on the roster would impact multiple other spots in the bullpen. It’s not impossible to keep him stashed away, but he may not be worth all the extra acrobatics. It's possible he'd break camp with the team and that Alcalá would start in St. Paul (since the latter can only be optioned now; he'll no longer be able to be farmed out once he accrues eight more days of big-league service), only to see a repeat of the Tonkin thing three weeks into the season: Castellano eats some innings, Alcalá comes up to refresh that spot on the roster, and Castellano hits the waiver wire, never to return.

Another option Twins Daily writer Cody Schoenmann explored is for the Twins to trade for Castellano, allowing him to be optioned to the minors, but at this time it seems like Philadelphia would have little reason to go that route. I’d guess the Phillies would prefer to see how things shake out, and are assuming there’s a pretty decent chance Castellano is returned to them in the end. (Besides, there are logistical hurdles there, too. Castellano would have to clear waivers before that kind of trade could be executed, even if it had been previously agreed upon.)

The Twins have been inactive in the Rule 5 Draft in recent years, so it was a surprise to see them make a selection. Though they were clearly enticed by Castellano’s upside, it would be an even bigger surprise if he actually stuck on the roster all season. Perhaps it’s best to return him to Philadelphia now and pivot to another plan that allows more flexibility in the bullpen.

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[Trov]

They brought him in to get their own look at him.  If they like what they see they can either trade from him, unless Philly will not agree to something, or they can bite the bullet and just deal with him as a mop up guy and maybe have days they cannot use him.  I get the more recent years teams love rotating the mop up guy through the minors due to the option years instead of total options.  The team will have to decided, is dealing with a few instances of short pen is worth holding him for the year.  It is harder for a team that wants to fight for division, but they can do it if they feel his arm is good enough. 

[mike8791]

Agree that Castellanos has to be cut.  He's just not ready, especially on a club that is supposed to be a strong competitor for Division.  Why not replace him with two potential starters, like Mathews or Morris, both of whom have shown much better ability than this guy?  After all, it's not unheard of in Twins' lore to start a potential starter in the pen.  Remember Santana?

[Karbo]

I hate to see a promising arm get away, but at this time it looks like there may not be a good answer. If it's win now time he will probably be gone soon. If they are building for a run after this year, then they keep him.

[Cory Engelhardt]

With the injuries to some of the bullpen guys, I don't know that we need to make the decision before opening day on if he is still on the roster or not. I'd be fine with having him be only the mop up guy for the first month or so and see if things improve. It's not like they can't find another mop up type arm at AAA or on the free agent market in early May. 

[IndianaTwin]

5 minutes ago, Cory Engelhardt said:

With the injuries to some of the bullpen guys, I don't know that we need to make the decision before opening day on if he is still on the roster or not. I'd be fine with having him be only the mop up guy for the first month or so and see if things improve. It's not like they can't find another mop up type arm at AAA or on the free agent market in early May. 

Exactly. Keep him. Use him in the lowest leverage situations at the beginning of the year. By the time you run into a couple of these scenarios, you well may have reached the point where a) he's been good enough to move a notch or two up the ladder or b) he's demonstrated under a truer test that he's not worth stashing for the whole year. It's not like the decision can only be made before March 26 or after October 1.

(And to anticipate a comment that's likely to come, I agree that you can't have a "low-leverage reliever." But there are always low-leverage situations that need to be covered by someone and it's logical to use the lowEST-leverage reliever there.)

[LambchoP]

I think it's obvious he's not quite ready for the majors, but he has a lot of potential that Id hate to see get away. If we kept him in the pen that would leave maybe one spot that we could rotate guys between the majors and St Paul. Is that enough? I think the best option would be to trade for him so we could send him back to AA and continue to develop him as a starter. If we need a multi inning pen arm someone like Morris might be a better option. It will be interesting to see how it plays out.

[Doctor Gast]

PHI would like Castellano back & MN would like to keep him. It's a game of chicken. PHI won't trade him because they think they can get him back. I'm split depending on the character of Castellano, his development would not be ideal under the MN situation, and how he'd react would affect whether to keep him or not. I'm a firm believer of correctly managing the BP & normally I'd say no to this idea because I wouldn't want someone in the BP that I couldn't send down. But I'm very impressed with this year's BP corp with the depth & the upper leverage they are capable of throwing. We have Varland, Topa & temporarily Alcala that can be optioned with likes of Funderburg & Dobnak that can come up to help out to cover any need where we can hide Castellano in the mop-up role until he graduates to low leverage. If we show PHI that we are able & determined to keep Castellano, it'll better our chances of winning this game of chicken & agree on a trade. We have a lot of promising young pitchers, Do we really need Castellano? I don't know; you can never have too much pitching.

"The team has also made sure to give him some tough assignments, the better to evaluate him against high-level competition."

Here I don't agree with the Twins. I'd take it easier on Castellano, let him build up more confidence before he's thrown into the mop-up role & the MLB coaches to work with him. There I'd slowly ease him into higher leverage & see what he really has.

[Muppet]

I'd just use him as mop up, or whatever, until they need to send him down for practical reasons then DFA him. I'm not going to worry about the off chance he becomes a star pitcher in 3 years if he is going to be a huge liability this year. There are better pitchers this year that could be up. This isn't going to be like giving up John Smoltz to get Doyle Alexander back. He's just an AA prospect. 

[BobAzar]

I mean, if hes out there throwing towels instead of balls, then there really isnt a place for him on the team

 

😉

[DJL44]

31 minutes ago, IndianaTwin said:

Exactly. Keep him. Use him in the lowest leverage situations at the beginning of the year. By the time you run into a couple of these scenarios, you well may have reached the point where a) he's been good enough to move a notch or two up the ladder or b) he's demonstrated under a truer test that he's not worth stashing for the whole year. It's not like the decision can only be made before March 26 or after October 1.

(And to anticipate a comment that's likely to come, I agree that you can't have a "low-leverage reliever." But there are always low-leverage situations that need to be covered by someone and it's logical to use the lowEST-leverage reliever there.)

Plus, the longer you delay the decision, the more likely it doesn't need to be made. Castellano could get better, which means you don't want to return him. He could get a minor injury, which means you can max out his injury rehab and give him some time in the minors. He could have a major injury, which delays the decision another year.

[IndianaTwin]

9 minutes ago, BobAzar said:

I mean, if hes out there throwing towels instead of balls, then there really isnt a place for him on the team

 

😉

But it really throws off a hitter's timing. 

[jmlease1]

I'd prefer that the Twins make a deal to keep Castellano and give themselves the flexibility to send him down to the minors. But right now with a couple of injuries to guys that I saw as being back end of the bullpen guys, there is a roster spot available, so if Philly thinks they can win the game of chicken before cut down day, I'm pretty confident they're going to lose that staring contest.

There other thing the Twins have going for them on this one is there are a couple of off-days built into the schedule early on to help handle a short start, and frankly the way the Twins rotation is shaping up and 8 guys in the bullpen, they can handle 1 low-leverage guy hanging in there, at least early on. Varland looks like he's going to grab a bullpen spot from the jump, and he's also someone more than capable of throwing 2 innings without needing 2-3 days off.

Castellano has shown he has the stuff worthy of protecting if you can manage it. Hope the Twins are able to thread the needle to keep him.

[TopGunn#22]

Castellano hasn't earned a spot in the Twins BP.  Yes, he's got an intriguing arm, but those kind of pitchers are a dime a dozen in Major League Baseball.  Throwing 97 mph as a relief pitcher isn't all that remarkable anymore.  

The Twins have a LOT of promising young pitchers that have options who could fill that role.  And I think getting guys like Matthews, Morris, Raya, Prielipp and others some big league innings is a good idea, even if they come out of the bullpen and not as starters.  I'd rather just roll with Funderburk.  He throws nearly as hard as Castellano and he's left handed.  

Absent working out a deal with the Phillies to acquire Castellano and giving him a chance to earn his way onto a major league roster once he progresses out of AA and up to St. Paul, he just hasn't done anything to warrant being a Minnesota Twin yet.   

[The Great Hambino]

If they're going to try to protect him and use him only in mop-up duty, then they better manage like they have a 7 man bullpen and adjust their starter usage accordingly.  It sounds nice on paper to let him grow into the role and ramp up his leverage gradually, but all it takes is a couple short starts/extra inning games in a row before they've potentially boxed themselves into using him in high leverage if the've been dipping into the pen earlier than necessary.  We saw it last year with Henriquez.  If they're not willing to push their starters deeper than normal, then they'll inevitably be choosing between Castellano and, say, Duran for the third day in a row, or Castellano and Alcala for a second inning when he wasn't 100% sharp.  Worth noting that they don't seem have the usual number of early-season off days built into the schedule this year

I find it hard to believe that they can't work out a trade if they really want to keep him that badly.

[PatPfund]

I like the potential, and Tonkin's injury in particular opens a spot for Castellano, but the kid is trying out for the team, and most of his outings have shortened his leash for sticking with the team. (I agree with the team's philosophy of having him face better opposition, because that's what he'd see after ST, and the  team needs to know now.)

The next week may bring a bit more clarity (in either direction), but if I had to make the call now, I'd preserve the potential asset by bringing Castellano north. On a very short leash, probably triggered by a terrible outing, early need, Tonkin's return (with his guaranteed contract), etc.

It was never much of a lock that a competitive team would be able to hold a Rule 5 pick long enough to keep him, so when/if he can't cut it, or they need the flexibility, drop him unless a decent deal can be made. This 'pen is really short on flexibility anyway (the pitchers with the options are among the best we have), which is likely to lead to Tonkin being DFA'd at some point as well. (Travis Adams is another possible St Paul Shuttle guy.)

Though who knows, maybe the kid surprises us, and unlocks something in the coming days and weeks! (The unexpected result is why we watch the games.)

 

[bean5302]

There are going to be 8 guys in the bullpen including guys who are back end relievers and fan favorites with options. There is no need to hold Castellano on the roster for the full season, they can waive him whenever. If the Twins are blowing out their bullpen in April in all tight games, they've got a heck of a lot more of a problem than their #8 bullpen arm.

This apparent vision of the Twins stashing Griffin Jax in AAA so Castellano can stay on the roster is ridiculous as is the expectation Castellano is going to come in to pitch the last 3 innings of game 163 this year because the Twins will have no other options and Rob Manfred has a group of hired goons insisting the Twins can never waive Castellano.

Castellano may not be good enough. The coaches will evaluate his stuff, what works and how well he can place his pitches. That said, Castellano's numbers were more impressive than any Twins pitcher not named Zebby Matthews in AA last year. Somehow, I think fans around here would be losing their minds at the suggestion Andrew Morris or Marco Raya be released.

[ashbury]

The problem with planning to use a guy for "low-leverage" innings is that those innings will come at inconvenient times. 

Say your starter has a bad game and you're behind 6-0 before he can even get out of the second inning.  It'll be low-leverage from here through the ninth, unless your hitters have some kind of outburst of their own.  You bring in your mop-up/long reliever, and he goes 3 1/3, say. No big rally, so you're still down 7-2 after five, say, with three or four innings to go (away vs home). Those innings will be low-leverage too. But the guy you tagged for those is done. Now you bring in a sequence of your one-inning guys, presumably in reverse order of ability and seeing if you can squeeze an additional inning out of one, but by this point it's not going the way your low-leverage plan envisioned.

And then the next day, you're winning 8-3 in the eighth, and your long-man low-leverage guy isn't available to mop up because he's resting.

And then you have an open date on the schedule, and then you encounter a string of five close games in which you wind up bringing in your low-leverage guy to face the #7 batter to start the inning and he walks a guy or two and suddenly he's facing the top of the order and you grit your teeth and you hold your breath and then possibly wind up taking him out anyway and burning another arm you didn't want to.

There exist low-leverage situations - plenty of them during a season in fact - but as Chief says, there are no low-leverage relievers anymore.  More precisely, no low-leverage roster spots in a major-league bullpen. The usage of starters has changed since I was a youth, and this is a consequence.

I still wanna keep Castellano, but he has to perform at least as well as the waiver-wire dreck that is available.

[HerbieFan]

3 hours ago, BobAzar said:

I mean, if hes out there throwing towels instead of balls, then there really isnt a place for him on the team

 

😉

No spin.  I bet that sucker moves like a knuckle ball! :)

[bean5302]

1 hour ago, ashbury said:

...There exist low-leverage situations - plenty of them during a season in fact - but as Chief says, there are no low-leverage relievers anymore...

Christian Vazquez isn't a catcher because he played DH in 3 games last year.

[DJL44]

Position players threw 7 innings last year and Dobnak threw 9.2. Cole Irvin had 3.2 innings and Jay Jackson pitched 26.1. There are definitely low-leverage innings to eat.

[Doctor Gast]

6 hours ago, BobAzar said:

I mean, if hes out there throwing towels instead of balls, then there really isnt a place for him on the team

 

😉

Yeah, IMO it's too early to throw in the towel.

[Doctor Gast]

You mentioned mop-up games when we were losing. I'd like to think that those mop-up games are from games we are winning too.

[ashbury]

2 hours ago, bean5302 said:

Christian Vazquez isn't a catcher because he played DH in 3 games last year.

Did you take my reference to Chief as some kind of appeal to authority fallacy?  I was crediting him.  His argument on the present subject is persuasive, unlike a pointless exaggeration of some other thing he may have said about something else.

[stringer bell]

Several teams have decided they couldn't keep their Rule V picks and only one (Athletics) has verified they will have their Rule V pick on the roster for Opening Day. There is a chance with Tonkin being injured that they can carry Castellano for the first couple weeks and hope his situation resolves positively. 

[bean5302]

54 minutes ago, ashbury said:

Did you take my reference to Chief as some kind of appeal to authority fallacy?  I was crediting him.  His argument on the present subject is persuasive, unlike a pointless exaggeration of some other thing he may have said about something else.

I'm saying I believe @USAFChief is wrong, and so are you. The argument there is no such role as a low leverage reliever because a low leverage reliever will sometimes (rarely) find themselves in a high leverage situation. I've addressed this previously with the actual rate of high leverage usage for a pitcher as defined by when a pitcher enters a game under a high leverage situation comparing Jay Jackson to Jhoan Duran.

It's the same argument as saying Christian Vazquez is not a catcher because he will be used as a DH or the real reason we had to get rid of Kyle Farmer is because he makes a lousy pitcher and had a 6.75 ERA last year with as many or more innings pitched than Daniel Duarte, Cole Irvin, Brent Headrick or Justin Topa.

The other argument which is used is the idea low leverage doesn't exist period because low leverage can become high leverage if the reliever gives up runs. It's a strawman seeking to manipulate the definition of a low leverage reliever. A relief pitcher who is considered low leverage is defined by when a team wants to use a reliever in regard to when the reliever enters the game, not when a reliever is pitching or exits a game. Jay Jackson pitched in 20 games last year. The Twins were 6-14 in those games. He took the loss in 1 game in his first 13 appearances and 18.0 innings pitched. His average leverage index entering the game was 0.49. He had two games where the Twins called his number in a higher leverage situation. That's a low leverage reliever. Of course, Jackson took the loss in both high leverage situations, but in only one situation was Jackson responsible for the runs on 4/6 where Jackson's number was called to face the meat of the LA Dodgers lineup in the 7th inning with the score 2-2 (Betts, Ohtani, Freeman). I don't care who walks to the mound in that situation, there's a high probability it doesn't end without a run scored. On 5/10, Jackson entered the game tied 8-8 in the 7th against the Blue Jays. Jackson managed an out and had a runner on 1st/3rd before Caleb Thielbar had one of his early season meltdowns and the game BB/1B/SF/BB.

There will be a whole bunch of innings pitched this year by relievers who are only on an MLB roster because of injuries, reputation or cost. There will be a bunch of relievers who pitch poorly. In fact, 25% of the more than 250 relievers with 30+ innings last year had an ERA of 4.50+. Their record? 162-169. Basically average. Is a "low leverage" reliever or basically a guy you'd rather not have pitching in high leverage situations going to significantly change outcomes compared to Michael Tonkin or this years version of Steven Okert or Ronny Henriquez? No. It's all the same.

[jmlease1]

One of the things to remember is the last guy in the bullpen can often go quite a while without actually pitching. With 8 guys in the bullpen, frankly there will be stretches where guys aren't getting consistent work. One of the reasons they shuttle guys down after one of those mop-up starts isn't because of real need but more about ensuring they have additional depth; it's not like the new guy comes up and pitches that same day. It's just risk-aversion, but the actual jeopardy is closer to the need for a 3rd catcher on the roster than a true danger. They just sell it better than Gardy used to about his 3rd catcher security blanket.

I'd still prefer to make a trade for Castellano to maintain flexibility and not risk getting squeezed, but we can ride with him as last man in the bullpen if Philly wants to keep playing chicken or make outrageous trade demands.

[jorgenswest]

Was there a recent pitcher on a competitive team that filled a low leverage/long relief role while staying on the major league roster all year?

I realize that this can break down into a painful back and forth about low leverage and long relief. I will do my best not to add to that pain by accepting your comp, I am truly interested in a comp of what we envision for Castellano.

Point me to a pitcher with the following characteristics. 

• 25 or younger
• no options
• remained on roster all year

Let’s do this in reverse. Let’s find a pitcher that fits those characteristics. I am curious about his role and how effective he needed to be to remain on the roster all year.

[DJL44]

11 minutes ago, jorgenswest said:

Was there a recent pitcher on a competitive team that filled a low leverage/long relief role while staying on the major league roster all year?

I realize that this can break down into a painful back and forth about low leverage and long relief. I will do my best not to add to that pain by accepting your comp, I am truly interested in a comp of what we envision for Castellano.

Point me to a pitcher with the following characteristics. 

• 25 or younger
• no options
• remained on roster all year

Let’s do this in reverse. Let’s find a pitcher that fits those characteristics. I am curious about his role and how effective he needed to be to remain on the roster all year.

Garrett Whitlock with the 2021 Red Sox.

 

[DJL44]

https://www.mlb.com/news/rule-5-draft-recent-picks-who-stayed-with-team