Checking In on Griffin Jax’s Transition to Starting Pitcher

[Cody Christie]

Image courtesy of © Jonathan Dyer-Imagn Images

When the Minnesota Twins traded Griffin Jax to the Tampa Bay Rays in exchange for Taj Bradley, the move immediately sparked debate about upside versus certainty. At the time, the Twins appeared to be dealing from a position of strength. Jax had become one of the most reliable relievers in the American League, while Bradley looked like the type of high-upside starter Minnesota’s rotation desperately needed. Early returns made the deal appear heavily tilted in the Twins’ favor. Bradley pitched like the club’s ace before a right pectoral injury landed him on the injured list.

Still, baseball trades have a funny way of evolving over time, especially when pitchers are involved. Now, the Rays are attempting something Minnesota talked about and quickly abandoned: turning Jax back into a starting pitcher. The funny part is, it might actually work.

Twins fans probably remember Jax’s rookie season well enough to understand why the organization gave up on the idea initially. During the 2021 campaign, Minnesota used him in 18 games, including 14 starts. The results were ugly. Jax posted a 6.37 ERA with a 67 ERA+ and a 1.35 WHIP while allowing nearly a hit per inning. Too often, lineups punished him the second and third time through the order.

At the time, he looked like a pitcher without a clear identity. His fastball command wavered, the secondary stuff lacked consistency, and he simply did not miss enough bats to survive in a rotation role. Then everything changed.

Beginning in 2022, the Twins shifted Jax into the bullpen full-time, and suddenly, he became one of the best relief weapons in baseball. From 2022 through 2024, he posted a 3.06 ERA with a sparkling 2.77 FIP while striking out 241 batters across 208 2/3 innings.

The transformation was dramatic. His slider became a legitimate wipeout pitch. The fastball played up significantly in shorter outings. More importantly, Jax started attacking hitters with confidence, rather than simply trying to survive. By the time the 2025 season rolled around, there was legitimate discussion about whether Minnesota should revisit the starter experiment. Unlike his rookie self, the more seasoned Jax actually looked equipped for it. His pitch mix had evolved considerably since moving to relief. He had sharpened his command, developed swing-and-miss stuff, and learned how to sequence hitters far more effectively. Frankly, he barely resembled the pitcher who struggled through 2021.

The idea made sense on paper. Unfortunately for Jax, the Twins needed him too badly in the bullpen. Minnesota entered 2025 leaning heavily on him as a high-leverage weapon, and the organization ultimately decided stability in relief outweighed the risk of another rotation conversion.

Then the season unraveled. The Twins collapsed under the weight of injuries, inconsistent pitching, and mounting clubhouse frustration. Jax’s final chapter with the organization included a tense interaction with former manager Rocco Baldelli on the mound at Target Field. Shortly afterward, his representation informed the club that a trade would be preferred. A few days later, he was headed to Tampa Bay.

Naturally, the Rays decided to get weird with it. Rather than fully stretching Jax out during spring training and immediately placing him into the rotation, Tampa Bay spent the early portion of 2026 using him in relief appearances, while gradually increasing his workload. It is a very Rays approach to pitcher development.

Recently, however, the Rays have started letting Jax work deeper into games. Across five starts, he has allowed only three earned runs over 19 innings with a 14-to-8 strikeout-to-walk ratio. His most recent outing against the Baltimore Orioles may have been his most encouraging yet. Jax tossed five innings, allowed three hits, surrendered just one earned run on a solo homer, struck out six, and walked only one batter.

Equally importantly, his workload continues to climb. Over his last three starts, he has averaged just over 60 pitches per outing, suggesting Tampa Bay is slowly removing the training wheels.

It's difficult not to play revisionist history with the trade. Earlier in the 2026 season, the Twins looked like clear winners. Bradley emerged as Minnesota’s top starter before his injury, while Jax remained somewhat of a question mark as a long-term rotation candidate.

But that equation may no longer be so simple. If Bradley’s injury impacts his long-term durability, while Jax successfully transitions into even a mid-rotation starter, the narrative around this deal could shift dramatically. Starting pitching carries far more value than relief pitching, even elite relief pitching. The Rays know that better than almost anyone. Bradley is back, and he looked like himself in his first appearance after the stint on the shelf, but it won't feel like he's out of the woods until he gets back to throwing full starts and puts that injury scare in the rearview mirror.

There's also an uncomfortable reality attached to all of this from Minnesota’s perspective. The Twins may have actually developed Jax into a starter without ever getting to enjoy the payoff themselves. His failed rookie stint likely came too early in his development. By the time he became polished enough to handle a rotation role, the Twins were too reliant on him in relief to make the switch. Tampa Bay, meanwhile, inherited the finished version of the pitcher and now gets to test the final stage of the experiment.

That does not make the trade a mistake. Bradley still has front-line starter upside when healthy, and the Twins desperately needed rotation help. Still, Jax’s resurgence as a starter adds an entirely new layer to the conversation. If he keeps pitching like this, Twins fans may soon find themselves wondering what could have been—although so far, Bradley is pitching well enough in his own right to deter those intrustive thoughts.

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What sticks out about Jax’s transition back to a starter? How should the Twins view this trade? Leave a comment and start the discussion.

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[rdehring]

Unless I missed it, Cody, you didn't mention one important fact of the trade. 

Jax will be a free agent, is it next year?  I know Bradley has been up and down, so he has accumulated some major league time, but he must have at least two years before free agency.  Or is it three?

[ashbury]

10 minutes ago, rdehring said:

Unless I missed it, Cody, you didn't mention one important fact of the trade.  TJax will be a free agent, is it next year?  I know Bradley has been up and down, so he has accumulated some major league time, but he must have at least two years before free agency.  Or is it three?

Very salient point!  b-r.com shows service time (years.days) for Jax as 4.091 and Bradley as 2.097.  I can't remember if these values are updated every day or if they reflect the status during the off-season, but since both have been on their respective rosters all year it doesn't matter.  Jax can be a free agent after 2027, Bradley after 2029.  Two years of extra control is huge, if comparing two valuable major league talents.

[Blyleven2011]

Griffin Jax  ( Captain Jax ) ...

I don't blame Jax for requesting a trade after that spat with rocco on the mound  , Jax is more intelligent , and Rocco insulted ,  embarrassed , disgraced or whatever you want to call it ...

Happy that Jax is getting what he wants to do and that is starting , he'd always been a starter in the minors and 1 year with the twins before being converted to relief  ...

The twins never put much value on Jax as a prospect  , i followed Jax in the minors and he had decent numbers in the minors but the twins exposed him to rule 5 claim a couple of years  , the year he was called up they brought him in just to eat innings as a starter ( because 9of injures ) and never expected much from him and then got lucky as he converted to reliever the next year  ...

[arby58]

1 hour ago, rdehring said:

Unless I missed it, Cody, you didn't mention one important fact of the trade.  TJax will be a free agent, is it next year?  I know Bradley has been up and down, so he has accumulated some major league time, but he must have at least two years before free agency.  Or is it three?

Jax is a free agent after the 2027 season; Bradley after the 2029 season - so the Twins have two more years of control. Also, Jax is 31 and Bradley is 25. 

[jmlease1]

well, let's see where Jax is when he actually starts handling a starters load for more than 3 outings before declaring the TB experiment a "success". His K-rates have dropped back down a ton and his FIP suggests he's been getting some good luck so far. It's also only 28 innings on the season, who knows?

The move to the bullpen was an excellent one for Jax; he quickly went from being an unimpressive starter that didn't appear to have a lot of upside to a guy who could be trusted to lock down games late & close. He upped his velocity and really developed the slider into a weapon (and anyone who thinks that Jax did all that on his own and the Twins staff were the ones holding him back somehow need a reality check).

Can he maintain that velocity over the course of a season? Can he hold up throwing 30-40 sliders in a night? Can he get his walks back down to a more reasonable proportion? Is he going to be giving up lots of longballs again now that he's starting? (he's been more homer-happy over the past 2 anyways...)

Is Jax starting because TB really believes in him as a starter, or is it because they don't have 5th starter they're happy with? (notably, they have 5 pitchers on the 60 day IL)

Regardless, Bradley has been great for the Twins and Jax is going to have to pile up a bunch of good starts to match him, even with Taj missing some time with an injury. Trade is still working out just fine for the Twins.

[C-Gangster]

2 hours ago, Blyleven2011 said:

Griffin Jax  ( Captain Jax ) ...

I don't blame Jax for requesting a trade after that spat with rocco on the mound  , Jax is more intelligent , and Rocco insulted ,  embarrassed , disgraced or whatever you want to call it ...

Happy that Jax is getting what he wants to do and that is starting , he'd always been a starter in the minors and 1 year with the twins before being converted to relief  ...

The twins never put much value on Jax as a prospect  , i followed Jax in the minors and he had decent numbers in the minors but the twins exposed him to rule 5 claim a couple of years  , the year he was called up they brought him in just to eat innings as a starter ( because 9of injures ) and never expected much from him and then got lucky as he converted to reliever the next year  ...

I think you're forgetting one thing. Yes some of Rocco's questions I can admit were a bit questionable. But Rocco was the manager I would like to say that neither side was in the wrong but when you look at it from the managers position he had to make a tough call and he gets a final say. Weather the fans or the players like it or not.

[WarPath1211]

In starts lasting over 3 innings so far, I'd say Jax has one excellent start (5 IP/1 H/1 BB/6 K/1 R), one okay start (4 IP/4 H/1 BB/3 K/2 R), and one bad start (5 IP/4 H/4 BB/1 K/0 R) that he was really lucky to not surrender a run in while giving up 4 hits and 4 walks with 1 strikeout in 5 innings. So while the ERA is shiny, the actual results have been mixed.

I'm not surprised Tampa is trying this because the trade didn't really make sense for them otherwise from a value standpoint. Even 4.5 years of a mediocre starter is probably more valuable than 2.5 years of a great reliever.

The way they've chosen to build Jax up is a little unorthodox, but I think it makes some sense. A lot of guys who move from the bullpen to the rotation fade late in the season as the inning count gets higher. But if they work up gradually so that they aren't expected to handle a starter's inning workload over a full season, maybe you can avoid that late fatigue.

As for how Jax will do in the future, it's hard to say. He's a very, very different pitcher from his early starting days with the Twins, and he will probably evolve more as he transitions to a starting role again. Jax didn't throw a single cutter in his relief appearances before beginning to start this year, but he's now throwing a cutter about 10% of the time in the starts, and his slider usage has gone down. In Jax's most recent start, he only threw his 4-seam fastball 8% of the time, a far cry from the 20%+ rates of his other starts. So there seems to be a good deal of tinkering going on.

[Cris E]

There's no way Jax is still in the majors without those years in the pen. As a starter he wasn't adding velocity, he was getting clobbered by hitters, he never had good length in games, and he wasn't young while doing it. The pen was the only available job for a 27 year old with his 92.7 mph FB and 7.4/9 K rate, especially since guys like JA "6.77 ERA in 20 GS" Happ were getting more starts for a 73 win team in 2021. 

Take the win, Griffin. I'm glad you're getting a chance to try it again. But no one should pretend this is completely a good thing, and it's mostly happening because he was so terrible out of the pen for much of April. 

[mluebker]

With the Twins, it rarely seems to matter what you were, only what they want you to be. Sometimes that works, other times you end up with unhappy ballplayers who may end up in Tampa Bay’s rotation or back in St. Paul trying to relearn to hit.

[Major League Ready]

4 hours ago, arby58 said:

Jax is a free agent after the 2027 season; Bradley after the 2029 season - so the Twins have two more years of control. Also, Jax is 31 and Bradley is 25. 

If they were to perform equally, Twins win this trade by a considerable margin.