Casey Mize Shows His Ace Card at Guaranteed Rate Field

Casey Mize was due for a good start. He delivered against one of the best offenses in the American League. A quick overview of his start last night.

Detroit Tigers fans were waiting for a start like this from Casey Mize since the day he was drafted. Now, that perhaps sounds unfair, but there are certain expectations that come with being the number one overall pick.

However, in his first career start in Erie, Mize threw a no-hitter, so Tigers fan held their collective breath as the zeros kept piling up. He was keeping the high-octane White Sox offense off the board for 5 innings before allowing a double to Yolmer Sanchez on a floating split-finger fastball. Sitting for a half-hour while the Tigers scored three runs to take the lead may have affected Mize, and he was soon replaced by Jose Cisnero.

But what was different than his previous start in Minnesota? Let’s take a look.

Swings and Misses

Mize threw just 76 pitches last night, compared to 83 against the Twins in his previous start, but according to Baseball Savant he was able to generate more whiffs — 11 to 7. He was using the same five-pitch mix of a slider, splitter, four-seam fastball, sinker, and knuckle curve, but everything seemed to have more action.

He threw his knuckle curve fewer times in this start than than he did against the Twins,  but he avoided any sort of pattern with it this time. In the 5th inning, for example, he threw a first pitch curve to Edwin Encarnacion, and in the same inning against James McCann, he used it to obtain his final strikeout of the day.

Instead of going to his split-finger, which is his main putaway pitch, he kept mixing his pitches to keep White Sox batters off balance. He did record two strikeouts with the splitter, but he also pitched backward a few times to get two Ks with a his nasty four-seam fastball with movement.

Striking First

Pitching coaches love to say “the best pitch in baseball is strike one,” and yesterday Casey Mize seemed to prove their point by throwing first-pitch strikes to 14 of the 18 batters he faced. That 77.8% first-pitch rate was by far the best of his short MLB career, almost 15% better than in his previous start.

Getting ahead in the count seems particularly important for Mize, because it allows him to stay unpredictable with his pitch usage. Two batters put the ball in play on the first pitch against Mize yesterday, but the other 12 hitters he got ahead against saw 4 sinkers, 3 four-seamers, 3 splitters, and 2 sliders for their second pitch. He stayed away from patterns and kept hitters off balance.

Weak Contact

The other thing Mize was able to do last night was avoid hard contact. His command and the movement on his pitches certainly played a part in that, but so did his pitch usage. His sinker is his worst pitch when it comes to generating swings-and-misses, but when it’s moving it generates a lot of weak contact. He threw it 28% of the time last night, his highest usage of the season, but batters pounded it into the ground, with an average exit velocity of just 82.3 mph.

Conclusion

None of this is groundbreaking, but we’re seeing a talented pitcher learn how to attack major league hitters. There are bound to be a few more bumps in the road, and he’ll need to continue building stamina, but last night was our first real glimpse of Casey Mize as a potential Ace.