A deep dive into Triston McKenzie’s recent struggles

The righty can rediscover his ace stuff by avoiding the middle of the strike zone

For the first month of the season, six starts, Triston McKenzie looked like the staff ace. With Shane Bieber’s velocity flagging and results coming up less than expected, McKenzie seemed poise to pay off on his former top prospect status.

As of May 8, McKenzie had a 2.76 ERA, 2.75 FIP, 26.1 K%, 7.8 BB%, and 0.3 HR/9 with opponents hitting .206/.289/.314 against him. Those numbers comfortably put him among the best pitchers in baseball; however, since then he has regressed heavily. Unfortunately, there’s really no one to blame but McKenzie, either, and this is borne out by the stats, as his FIP and HR/9 have gone from 13th and 11th best among qualified starters, respectively, to 73rd, dead last.

The fact that his home run rate and fielding independent pitching have skyrocketed in tandem is no shock or surprise, of course. No defender on earth is going to stop Gary Sánchez’s blast from Monday night. McKenzie, however, could stop the damage with some adjustments.

As seen in the image below, during the first month of the season, McKenzie was working in the zone a lot, but he was working more down, primarily in the lower-left corner (catcher’s view), rather than over the heart. Since May 8, he’s stopped working as low in the zone but has continued to throw pitches middle-middle. It will surprise no one to learn that 22% of his middle-middle pitches have been hard hit, with an average exit velocity of 95.8 mph.

In a somewhat strange development, balls middle-middle have only been hit over the fence twice, which is fewer than those middle-up and lower right in the zone (three each). But middle-middle pitches are batting practice pitches for major league hitters regardless of the velocity, as seen in the .770 expected slugging on those pitches.

The home run ball has been an issue for McKenzie his entire MLB career thus far, with a cumulative 1.66 HR/9 rate through 233.2 IP. However, the problem was not always as clear-cut as it has been this year. As seen in the image below, McKenzie avoided throwing meatballs middle-middle very well last year.

Most of the damage hitters did against McKenzie in 2021 came on high pitches. Batters had an expected slugging of .784 in the upper left and .725 middle-up in 2021. In 2022, McKenzie has managed to limit the damage (relatively) when he throws in those same zones to .501 and .657 xSLG. But his biggest strength, where he hurts batters the most, is by working low in the strike zone.

Per his swing-take chart, we can see the actual value that pitching to those shadow part of the zone has for McKenzie, but further breaking it down by pitch gives even more insight.

The fastball is drifting to the heart most often, but is also working up. I would never suggest McKenzie start throwing his breaking pitches up in the zone (unless we want to see him give up even more home runs), but if he were to throw the fastball down more often he could perhaps be more effective with his breaking pitches.

Despite the home run surge, McKenzie’s weighted pitch value on his fastball is not terrible, coming in at 0.26 (28th in MLB); however, his slider’s weighted value (-2.54) is second-worst only to Zac Gallen among qualified starters. Because these two pitches have similar rotation (both in direction and rpm: 2,300 and 2,173 for the fastball and slider, respectively), it seems like they could play well off each other if they were not so spread out in their average location. Right now McKenzie seems to be using his curveball and slider in tandem because of their similar horizontal break toward the first base side. His fastball runs slightly more to the third-base side, but the similarity in vertical break to the slider makes me think it could still be more effective if the two were located more closely together.

But even if McKenzie does not start locating his fastball and slider similarly, working down in the zone rather than in the heart would be a tremendous benefit. There are a number of factors that could be contributing to balls leaking middle-middle and hurting McKenzie, from the physical to the psychological, and I don’t have nearly enough information to pinpoint any of them. But I can say with certainty that pitching middle-middle is hurting him right now.

In his brief career, McKenzie has already been through a lot and overcome a lot as well. After not pitching competitively at all in 2019 and never throwing a single inning above Double-A, he came in and struck out 11.34 batters per nine at the big league level in 2020. This is not a guy I would bet against. So I am hoping he’ll find a way to avoid those middle-middle pitches, and soon, because the ace version of McKenzie was a guy I was really excited about.