Detroit Tigers' Casey Mize shows four-pitch mix to hitters for first time since surgeries

Detroit Tigers right-hander Casey Mize, the No. 1 overall pick in the 2018 draft, stepped on the mound at Comerica Park and completed his first live batting practice session before Saturday's game against the Houston Astros.

He threw fastballs, splitters, sliders and curveballs.

It's been a long time coming.

"I've thrown like a million bullpens, so it's good to actually have guys in the box and be on the game mound," Mize said. "I just love to pitch, and it's good to do it with a hitter in the box. My body feels great, and I'm happy to knock down another step of this really long process. But we're not at the finish line yet."

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Mize looked incredible throughout the 20-pitch live batting practice session, the latest accomplishment in his return from elbow surgery and back surgery. The 26-year-old underwent Tommy John surgery on June 15, 2022.

His high-powered fastball stood out as his best pitch. He placed an emphasis refining his four-seam fastball — which averaged 93.4 mph over two starts in the 2022 season — at the beginning of his rehab process.

"A lot more four-seamers is what you're going to see," Mize said. "I've been really pleased with the fastball throughout this whole thing. Velocity and whatnot, I feel really good with where I'm at and feel like it's coming out pretty good. It feels like I'm not trying to overdo it, but I'm also not cautious. I'm letting loose out there."

He also evaluated his three secondary pitches.

"The split feels good," Mize said. "The curveball feels great. I'm really pleased with the process of that throughout this process. The slider is fine. I need to hone that in a little bit. That's probably been the last pitch to come throughout this whole thing, so I need to keep working on that one."

Mize faced catcher Carson Kelly, a right-handed hitter, and center fielder Parker Meadows, a left-handed hitter, in his first of at least two live batting practice sessions. The Tigers simulated four plate appearances — five pitches per plate appearance — to reflect a one-inning workload.

"He was the first guy I caught," said Kelly, who signed with the Tigers on Aug. 19. "I was like, 'This guy is really good, really good.' Four-pitch command, electric stuff, all plus-plus pitches. It was fun to face him and see it from the batter's box, but I think I'd rather be behind home plate."

"He looked really good," Meadows said. "Electric fastball. The splitter looked really good."

Mize said his fastball sat around 95 mph, but Meadows revealed a different velocity. Austin Tripp, the Tigers' video coordinator, stood behind home plate — next to pitching coach Chris Fetter — and viewed the Trackman data from Mize's live batting practice session on an iPad.

"He was 96-97," Meadows said.

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Left-hander Tarik Skubal, who returned from left flexor tendon surgery at the beginning of July, watched the new-and-improved Mize from behind home plate, too. Almost all of the pitchers, and almost all of the position players, supported their rehabbing teammate.

Skubal noticed something different.

"That's the best I've ever seen him move for as long I've been with him, so since 2018," Skubal said. "He looks clean. It looks easy, too. It doesn't look as forced. Everything flows down the mound. I'm excited for him."

The refinement of Mize's delivery started with back surgery and continued with a deep dive into the data. He studied the biomechanics of his delivery alongside Fetter and assistant pitching coaches Robin Lund and Juan Nieves, then completed a three-phase process to dissect each part of the delivery, which included new drills.

Mize learned to get his body in optimal positions throughout his delivery.

"It's not a finished product," Mize said, "but just having the procedure on my back, it's not only been a life-changing surgery, but it's allowed me to really get into positions that I feel really comfortable in. I haven't been able to feel that way in a long time, so I'm really excited about that."

Manager A.J. Hinch has praised Mize for sticking to the schedule of his rehab program and maintaining his work ethic in completion of each task along the way. The regular bullpen sessions began more than 65 days ago, on June 21, with 10 fastballs in a short-box bullpen.

It was a treat for Hinch and the Tigers to watch Mize face hitters for the first time. After all, he hadn't competed against hitters since May 12, 2022, in a failed rehab start with Triple-A Toledo.

"He was really exceptional," Hinch said. "It was a live BP session, so you have to keep it in context, but as far as delivery, arm action, freedom, he's already hard on himself about not executing pitches and not being perfect, which tells me he's thinking about pitching and not thinking about rehabbing."

So, what's the next step?

"The next step is to increase volume," Mize said.

Mize, who has a 4.29 ERA in his 39-start career, is scheduled to throw his second live batting practice session next week during the Tigers' four-game series against the New York Yankees, from Monday through Thursday, at Comerica Park.

Returning to the Tigers in the 2023 regular season appears unlikely because there are only 33 games remaining, but that doesn't rule out the possibility of a rehab assignment in minor leagues.

"On average, guys throw two or three or four of these," Hinch said. "I'll let you know when it's the end."

Contact Evan Petzold at epetzold@freepress.com or follow him @EvanPetzold.

This article originally appeared on Detroit Free Press: Detroit Tigers' Casey Mize shows full arsenal in first live BP