Steven Matz is set to make his 2018 debut this afternoon as the Mets play their series finale against the Cardinals. He’s coming off a very bad season that saw him make just thirteen starts, pitching 66.2 innings with a 6.08 ERA and 5.05 FIP in the process. His season was both delayed and ended prematurely by injury, and there’s a pretty good chance that he was never quite 100 percent while he was actually out there on the major league mound.
While Matz was never among the league leaders in strikeout rate, he had been much better in that regard in 2015 and 2016 than he was last year. He went from 22.8% to 23.6% to 16.1% in K percentage. That rate last year was just two-thirds of the year before, a drastic drop, and among the 178 pitchers who threw at least 60 innings as starters, it ranked 152nd.
Drilling down a bit more, it wasn’t shocking that Matz saw the K rate drop. His swinging strike rate was just 7.1%, down from 9.8 in 2016 and 8.3 in 2015. The average major league starting pitcher had a 9.8 percent rate last year, putting him well below average. And per Brooks Baseball, his slider and curve saw the biggest drops in whiff rate—though all of his pitches got fewer swings-and-misses than they had in the past.
In terms of usage, Matz threw the slider very infrequently, something that had been mentioned as a way of keeping his arm healthy during the 2017 season. He threw the curve more often than he had in the past, but neither pitch fared particularly well.
Velocity wasn’t a huge issue, but Matz’s sinker came in about two-thirds of a mile per hour slower than it did the year before. And his changeup was thrown about half-a-mile per hour faster. Reducing the gap between those two pitches isn’t usually ideal.
Spring training stats should never be taken too seriously, but Matz struck out 21 batters in 20 innings in those exhibition games. Taking K/9, which is a bit crude in the first place, seriously from those games would be a mistake, but at least it wasn’t like he wasn’t striking anyone out.
It’ll take much more than one start to reach any conclusions about what kind of pitcher Matz is this year. But as he begins his season today, it’s worth keeping an eye on the swings and misses. Even if the strikeouts aren’t there today, a high whiff rate would be an encouraging sign. And while velocity isn’t everything, it’d be encouraging to see him throwing as hard as he did in 2015 and 2016, even if that was just a shade above what he threw last year. It’ll always come down to health with Matz, but perhaps swinging strike rate and velocity will give us a little bit of an indication of what might follow.