For his first three seasons with the Tigers, Casey Mize pitched through sometimes searing pain in his leg, stemming from a back injury that required surgery last offseason. Now he's pain-free and pitching better than ever.
Mize threw six shutout innings in the Tigers' 6-1 rout of the Twins on Sunday to record his first win in two years and lower his season ERA to 2.95, a mark befitting a former first overall pick. His fastball was sizzling as it has been for most of the spring, a marked difference from seasons past.
Mize told reporters in Minnesota over the weekend that prior to back surgery in 2022, which came on the heels of Tommy John that same year, he was crippled by pain in the sciatic nerve running down his left leg anytime he pitched. It happened whenever he landed firmly on his lead leg, which is how he generates fastball velocity, and forced him to compromise his mechanics.
Sciatica pain, per the Mayo Clinic, is most often triggered by a herniated disc putting extra pressure on nerve roots in the lower back, which sends a jolt down the buttocks and the back of the thigh and calf that can sometimes feel like an electric shock. Mize said that he experienced the pain "down to my left foot."
"When I would land, I couldn't straighten it or else it would shoot nerve pain down my leg," Mize said, via the Free Press. "Physically, my body was saying, Stay out of these positions, it hurts, it's hurt like this for a while. Now I'm pain free, and it took a while for my brain to recognize that and my body to follow suit. Now I'm able to stick the leg in the ground and brace it really hard. That energy transfer is happening a lot better than when I wasn't able to do that in the past."
The result is that Mize is throwing a lot harder, which helps in outings like Sunday's when he otherwise didn't have his best stuff. His average fastball velocity is at 95.3 mph through four starts, up from 93.4 mph the last time he pitched in 2022. Meanwhile, the expected batting average against his fastball is down from .306 to .251, the expecting slugging percentage is down from an alarming .767 to .395, and the whiff rate is up from 10.5 percent to 16.7. The average exit velo is down from 96 mph to 91.9.
Mize missed most of 2022 and all of 2023 rehabbing from his surgeries. On his long road back to the mound, he put in a lot of work in the weight room, which helped him add close to 20 pounds of muscle. More importantly, he said he did a lot of "dry work on the mound with med balls to re-pattern" his movements. Essentially, to reclaim his old delivery.
"I had to convince my brain, It's OK, it doesn't hurt, you can move this way," said Mize. "We did months and months of work on that, which was difficult. It took a lot of work, but I'm on the other side of that now."
That growth, coupled with the early-season results, has restored Mize's faith in his fastball.
"In the past, 1-1 (count), 2-1 (count), here comes the slider because I don't have a good enough fastball in a fastball count to beat you. Now I feel like it's not always going to be a slider," he said. "I feel pretty confident, 2-0 (count), here's my best heater versus your best swing, let's see what happens. I feel better about that now. And I think it helps my other stuff play a little bit better."
Against the Twins, Mize delivered his first scoreless start of at least six innings since April of 2021. And he did so on a day that he said he was "just trying to get outs with what I had." He called it "a battle." A.J. Hinch said it "wasn't without a fight and a grind." Mize allowed five hits and a season-high three walks, but also got a game-high nine swings and misses: four with his fastball, five with his splitter.
"If I leave the game and there's a zero in the run column, it's hard not to be happy with that," said Mize. "I'm happy to compete and give us a chance to win, and that's what we did."