What's Eating Minnesota Twins Bullpen Ace Griffin Jax?

[Matthew Lenz]

The Minnesota Twins entered the season expecting to have one of the best bullpens in all of baseball. While they've been good to start the season, they haven't been as effective as many expected them to be. In particular, one of their relief aces hasn't been as effective as he has in previous years. Let's dive in.

Image courtesy of © Matt Krohn-Imagn Images

It's been three years since Griffin Jax converted into a reliever and quickly became one of the best high leverage arms in all of baseball. After getting past the speculation and idea that he might return to the rotation in 2025, it was the expectation that he would be a two-headed monster with Jhoan Durán at the back of the Twins bullpen. Heck, some might even say that Durán is the “closer” by name but that Jax really is the star of the relief group.

Alas, three weeks into the season and Jax has already coughed up two homers on 12 hits in 7 ⅔ innings. He's getting rocked and trending toward a major departure from his past numbers. Surely, there has to be a change in his pitch profile that has led to him not only being more hittable but to being hit harder than ever before, right? Not so fast.

Despite the lackluster start to the season, Jax is still striking out 29.7% of batters (about five points less than in 2024) and walking an impressive 2.7% of batters. The velocities of each pitch in his arsenal remain the same from 2024, although he's featuring his changeup more to lefties and relying less on his fastball which had a Run Value (RV) of nine in 2024. Having thrown just 135 pitches so far this season, it's probably too early to read too much into his pitch mix, especially when he’s seen nearly a 50/50 split of left handed batters and right-handed batters.

If we look into his movement and spin rates, which may be equally as insignificant this early, we’ll see a slight change in his profile. It appears his sweeper, his most oft used pitch, has less sweep but his fastball has slightly more rise to it. The graphic below, broken down by month, shows that his spin rates tend to increase as the season goes on, indicating this is not out of the ordinary for him this early in the season.

For reference, despite the lower spin rates, he still carries gaudy strikeout and walk rates with a 2.71 FIP in March and April. Again, it's too early to take anything meaningful away from the data presented so far but the contour profile of his pitches may be telling indicators explaining his early season struggles.

Remember when I said his sweeper has less sweep? This has resulted in him leaving the pitch over the middle of the plate (dark red blob sitting middle-middle isn't good), whereas in 2024 the pitch typically was low, away, and out of the zone to right-handed batters. While it hasn't resulted in additional home runs we've seen a significant increase in opponent’s batting average and especially their slugging percentage in the early going. Moreover, Jax has also been missing with his fastball up in the zone. This has resulted in a .429 opponents batting average, a 1.289 slugging percentage, and two home runs against the offering. Last season, he allowed just two home runs off the pitch all year.

So, are we concerned about Jax’s effectiveness? Not yet, but it's something to keep an eye on in the early going here. It's a good sign that we aren't signing diminished velocity or stuff from the 30-year-old, as relievers are the most volatile position group from year-to-year. Right now the problem seems to simply be execution. Especially with such a limited sample, it very well could be that Jax will find his groove and get back to hitting his spots as the year rolls on.

What is your level of concern with Jax’s hittability in the first weeks of the season? Join the conversation in the comments!

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[jmlease1]

This is always the challenge with relievers: the samples are small enough that it's hard to be sure from the data whether there's something actually wrong, or it's mostly just bad luck (on jax's part) or good luck (on the hitter's part). Right now it doesn't look like there's anything mechanically wrong with him, so I'm going to keep my panic levels a little lower. 

If Brock Stewart were already up to give the team another high-leverage arm they were confident in, it would be easier on everyone, though.

 

[Patzky]

17 minutes ago, jmlease1 said:

This is always the challenge with relievers: the samples are small enough that it's hard to be sure from the data whether there's something actually wrong, or it's mostly just bad luck (on jax's part) or good luck (on the hitter's part). Right now it doesn't look like there's anything mechanically wrong with him, so I'm going to keep my panic levels a little lower. 

If Brock Stewart were already up to give the team another high-leverage arm they were confident in, it would be easier on everyone, though.

 

I think he (Stewart) is in a rehab stint in Fort Myers. Maybe by next weekend he'll be with the Twins 

[Blyleven2011]

Jax should be fine , he's a bulldog and has the intelligence to work it out ...

I'm not concerned with Jax  , I was concerned when they left him unprotected in the rule 5 draft 2 years in arow , I followed him in the minors as a starter and always liked what I saw  ...

Aye aye captain ...

[Fire Dan Gladden]

I am going to guess that Rocco is somehow to blame here...🤨

[darwin22]

4 hours ago, Blyleven2011 said:

Jax should be fine , he's a bulldog and has the intelligence to work it out ...

I'm not concerned with Jax  , I was concerned when they left him unprotected in the rule 5 draft 2 years in arow , I followed him in the minors as a starter and always liked what I saw  ...

Aye aye captain ...

Easy to post 4 hours later, but ANOTHER meltdown by Jax tonight is beyond concerning.  4-1 lead totally p^ssed away.  Just another reason NOT to invest any time into this team.

[BillyBallLives]

What ever mojo he had is gone.

Now he has something to fix. 

----

"I just found myself always gravitating back toward the bullpen. I’m sure part of it is because I failed as a starter at the big-league level, and found some pretty good success in the bullpen. But at the same time, I just feel like my personality just thrives in that back-end, late-inning role now. I almost just look at it as, ‘If it’s not broken, why bother trying to fix it?’”

 

Griffin Jax on staying in the bullpen (The Athletic)

[S Bart]

It is time to move Jax to another role in the bullpen until he can get on track.  This 8th inning set-up role simply isn't working. There are other choices. Coulombe or Varland are possibilities, and Stewart is on his way back. The Twins may/will have empty stands next week again. 

[miller761]

Agree, Can't keep giving games away while he figures it out. I believe he will figure it out but put him in some less stressful situations. We have other options in the 8th. The other question I have is why can't Duran navigate the tough part of the order in the 8th and Jax or someone else the 9th? This happened las year.

[h2oface]

If you aren't concerned about Jax, it is concerning. He has officially earned concern in 2025. And the teammates in TBBIMLB are again giving up inherited runs like....... like....... like Jax is giving up hits.

Baldelli will keep pretending it isn't happening, too. Believe in the process and not the results.

[HrbieFan]

12 hours ago, Fire Dan Gladden said:

I am going to guess that Rocco is somehow to blame here...🤨

The idiot does keep running Jax out to blow leads. Maybe use him in mop up rolls until he gets his head on straight again 

[LambchoP]

There has to be a little concern when our best pen arm is getting shelled every outing and giving up games. They have to give someone else the set up role for awhile until he gets right. Sands would be the logical answer but he hasn't looked sharp either. Hopefully Stewart is back soon and can stay healthy. If Jax and Sands continue to struggle, we might have to consider calling up one of the pitching prospects from St Paul. Zebby and Festa will be needed in the rotation but Morris, Adams or Raya could help out in the pen this year. 

[Richie the Rally Goat]

19 minutes ago, LambchoP said:

There has to be a little concern when our best pen arm is getting shelled every outing and giving up games. They have to give someone else the set up role for awhile until he gets right. Sands would be the logical answer but he hasn't looked sharp either. Hopefully Stewart is back soon and can stay healthy. If Jax and Sands continue to struggle, we might have to consider calling up one of the pitching prospects from St Paul. Zebby and Festa will be needed in the rotation but Morris, Adams or Raya could help out in the pen this year. 

Agreed, except Morris will be needed in the rotation too

[jmlease1]

12 hours ago, darwin22 said:

Easy to post 4 hours later, but ANOTHER meltdown by Jax tonight is beyond concerning.  4-1 lead totally p^ssed away.  Just another reason NOT to invest any time into this team.

My concern levels have gone up for sure. back to back implosions, only 1 "clean" inning all season...he needs a re-set.

[HerbieFan]

Seems like a complicated way of seeing his stuff is still really good but his location isn't.

[Patzky]

19 hours ago, Patzky said:

I think he (Stewart) is in a rehab stint in Fort Myers. Maybe by next weekend he'll be with the Twins 

Stewart has been activated and Funderburk assigned.

[Patzky]

3 hours ago, LambchoP said:

There has to be a little concern when our best pen arm is getting shelled every outing and giving up games. They have to give someone else the set up role for awhile until he gets right. Sands would be the logical answer but he hasn't looked sharp either. Hopefully Stewart is back soon and can stay healthy. If Jax and Sands continue to struggle, we might have to consider calling up one of the pitching prospects from St Paul. Zebby and Festa will be needed in the rotation but Morris, Adams or Raya could help out in the pen this year. 

Stewart has been recalled and Funderburk reassigned as of noon.

[Richie the Rally Goat]

21 hours ago, HerbieFan said:

Seems like a complicated way of seeing his stuff is still really good but his location isn't.

The last outing his breaking ball wasn’t breaking enough. A pitch that last year would have hit the catchers mitt inside and thigh high was dead center of the zone. Two outings ago he adjusted for the lack of break with a back door slider low and away, this go around he didn’t…