Here’s how Mize’s splitter became so filthy

Casey Mize and his split-finger fastball lived up to their billing in his big league debut.

Scouts considered Mize's splitter the most devastating pitch in the 2018 Draft, where the Tigers selected him No. 1 overall. It continued to overmatch hitters during his 26 starts in the Minors, during which he posted a 0.88 ERA in high Class A and threw a no-hitter in his first Double-A outing.

Last Wednesday night against the hot-hitting White Sox, Mize dealt with his splitter for four innings before running out of gas in the fifth. He struck out Yoán Moncada, Zack Collins, Tim Anderson and José Abreu with splits in the first three innings, and also used it to induce groundouts from Moncada and Nomar Mazara. In the fifth, he left two splitters up that turned into a Collins double and Anderson single, and he also threw a quality split to Anderson that resulted in a seeing-eye single.

All told, Mize -- the Tigers' No. 2 prospect and No. 8 overall -- threw 19 splitters and got six swings and misses for a 32 percent whiff rate. He allowed three runs in a 4 1/3-inning no-decision while becoming the first Tiger ever to strike out seven batters without a walk in his initial big league outing. No pitcher had done that since another former No. 1 overall pick, Stephen Strasburg, in June 2010.

Mize averaged 94.2 mph with his fastball, 88.8 mph with his slider and 81.1 mph with his curveball while throwing 49 of 73 pitches for strikes. But as usual, his splitter was his most dominant offering, and the Statcast metrics back it up.

Mize's splitter sat at 85.9 mph while averaging 38.7 inches of vertical drop and 13.2 inches of horizontal break. In the four years (2017-20) for which data is available, no regular big league pitcher has combined that kind of velocity and life on their split. Among pitchers who have thrown 19 or more splitters, Mize ranks 12th in velocity, fourth in depth and sixth in run.

Mize's ability to locate his splitter where he wants takes it to another level. Hitters can't just lay off his split and watch it dive out of the strike zone because he can clip the bottom of the zone with it at will despite its exceptional life.

Detroit assistant GM David Chadd, who previously was the scouting director with the Marlins, Red Sox and Tigers and was heavily involved in the drafting of Mize, said he never has seen an amateur with a splitter as nasty. He compared it in quality to the curveball of Josh Beckett, the No. 2 overall pick in 1999 by Florida when Chadd was a crosschecker there.

"I can't remember anyone as an amateur who had a split like that with the confidence to throw it and the ability to command it," Chadd said. "It's a devastating pitch, definitely a strikeout pitch.

"As a hitter, you can't sit up there and sit on the split because the other pitches are so good. The more confident he gets throwing all of his pitches and command his fastball, it's going to make his split even better."

During a 2019 Spring Training interview, Mize said he started employing a splitter at Springville (Ala.) High after he fell in love with his slider, lost the feel for his changeup as a result and needed an alternative. He initially threw the pitch with his index and middle fingers between the seams and didn't use it much as a freshman at Auburn.

Under Hal Baird, who coached at Auburn from 1985-2000 and set a school record with 634 victories, a number of pitchers found success with a splitter. The pitch helped John Powell become the NCAA Division I career strikeout leader with 602. It also contributed to Scott Sullivan spending a decade in the Majors and Tim Hudson making four All-Star Games and winning a World Series.

Current Auburn coach Butch Thompson thought about that history when Mize needed a third pitch as he became a full-time starter as a sophomore. Sullivan and Thompson are neighbors, and he sent the coach a picture of the split grip he used. Thompson and Mize began tinkering with it, and the coach suggested he use his index finger to pull on the seam on the left side of the ball and position his middle finger in between the horseshoe shape on the other side of the ball.

Mize said that the new grip added more velocity, run and sink to his splitter, and he also was able to command it better. He excelled in his final two college seasons, leading NCAA D-I in strikeout/walk ratio as a sophomore (12.1) and ranking fifth (9.8) as a junior.

"He picked up that split and the command came very soon," Thompson said. "It was such a weapon. We started with Scott's grip and then we were just making the pitch fit Casey. You start with the grip, then you get the pressure points right and you make it your own.

"His fastball is such a better pitch with the split in the hitter's mind. You've got to show the split some respect."

The Tigers drafted Mize first overall and gave him a $7.5 million bonus in hopes that he would lead a pitching revival that would carry them back to contention. With bat-missing left-hander Tarik Skubal joining Detroit's rotation at the same time as Mize and first-round righties Matt Manning and Alex Faedo not far behind, that bright future shouldn't be too distant. And it will feature plenty of unhittable splitters from Mize.

"Sometimes it's spiking or sailing here and there, but I'm never going to give up on the split," Mize said last spring. "I need that pitch to be on, to honestly be successful. If I don't have a feel for it that game, I'm going to keep throwing it."