Detroit Tigers: Michael Fulmer’s curveball is back and better than ever

Detroit Tigers reliever Michael Fulmer has re-introduced his curveball to his pitch mix for an even more dominant product

Detroit Tigers reliever Michael Fulmer is proof that not all Tommy John Surgery recoveries are created equal. With modern medicine and the continued frequency of these surgeries, fans sometimes assume that a player will be out for 12 months and then return throwing harder than before. In some cases, that certainly is true.

It wasn’t for Fulmer, though, who was deployed in a hybrid role for 2020; a year in which results and peripherals were equally as shaky and had many questioning his role with the team moving forward. 10 games, 27.2 innings, 45(!) hits, 27 earned runs, 12 walks, 20 strikeouts. A WHIP north of 2.0. An ERA of 8.78 with a FIP only suggesting moderately bad luck.

The sinker and four-seamer were both down almost 3 mph each on average from his 2018 numbers. In a league that is trending toward velocity, there is a big difference between 96 and 93 to hitters. Likewise, it had to change the game plan and mindset of Fulmer, who was undoubtedly accustomed to missing bats with his fastball. His whiff rate with his four-seamer was 29.4 percent in 2018; just 8.5 percent in 2020.

The Detroit Tigers and manager AJ Hinch astutely assigned Fulmer to a bullpen role for 2021; a year in which Boyd, Turnbull, Mize, Skubal, and Teheran occupied rotation spots. It was always silently assumed that Fulmer would thrive in relief. His stuff has always been heavy and devastating; lots of fastballs and sliders with a fastball that could have even found a smidge more when compartmentalized to an inning or two.

Most expected the move to work out, but I’m not sure anyone could have predicted things to go this well. Fulmer has supplied a 1.7 bWAR; 3.12 ERA across 66.1 innings, 66 hits, 19 walks, 70 strikeouts. His presence coupled with Gregory Soto and Jose Cisnero presents paramount reasoning for the club’s achievements despite the injuries they’ve dealt with in the rotation.

Then comes the curveball.

The Freep has done an admirable job covering the new development. Evan Petzold talked about the process with pitching coach Chris Fetter here; Chris McCosky also talked about it in his recent piece here. It’s back and features above-average horizontal movement attributes and a .000 batting average against. His very first strikeout with it in 2021 came on September 5th on a 2-2 pitch to Kyle Farmer:

Since then he’s thrown 31 more of them and hitters have yet to tag it. Overall, it boasts a 54.5 percent whiff rate and nearly 200 more RPMs than last season.

It’s a development that has many wondering, “What in the world is a pitcher with two different fastballs, a nasty slider, a changeup, and a new curveball doing in the back-end of a bullpen?” Supposedly, according to McCosky, those conversations on bullpen vs rotation are happening and Fulmer seems content with whatever they decide; a decision that might be aided by the injuries that will pour into 2022.

Regardless, Michael Fulmer’s curveball is yet another nasty weapon for him to deploy when he’s ahead. Since he started throwing it, he’s fired 9.2 innings of scoreless baseball. Fulmer is dynamic with this new pitch, and I have a hunch that Hinch and pitching coach Chris Fetter will leverage this development to maximize his impact on the field.