Zach Plesac should try slowing down to find success

Zach Plesac has started to lean on his fastball more than usual in 2021. Maybe he shouldn’t.

It seems like a million years ago, but just last season Plesac looked every bit the Robin to Shane Bieber’s Batman. Whether the 2.28 ERA, the strong if not exceptional 3.39 FIP, the 27.7% strikeout rate, and the 2.9% walk rate — it looked, at first blush, like Plesac had made The Leap. And in such a short time too, after a rookie year in 2019 where he looked solid if unspectacular, great middle to back of the rotation kind of filler that every team needs. It seemed like we had another product of the Cleveland Pitching Factory off the assembly line and ready to vaporize hitters.

Then this year happened, and even with a freak injury, it’s hard to call Plesac anything but bad right now. His ERA is two and a half runs higher than a year ago even after the best start of his season against Texas; his FIP taking that ride nearly as far, while his strikeouts and walks have gone in opposite directions from a year ago. In fact, outside of the walk rate, which is now merely extremely good instead of Olympian, he’s gotten generally worse.

Pitchers have ebbs and flows, especially in a young career. And last year was just an oddball of a season, it’s hard to really take a lot of it at face value. I don’t think Plesac is a 2.28 ERA kind of pitcher, any more than Bieber is Jesus Christ mk.2 on the mound or J.D. Martinez was going to keep his .213/.291/.389 line into 2021. Plesac doesn’t have the raw untouchable stuff that separates the superstars from the rest. He was always more than the sum of his parts when it comes to his repertoire.

To be successful in the majors Plesac has had to lean on craft and guile even as a pitcher with fewer than 300 big league innings under his belt. That’s why this year is so strange. For whatever reason, Plesac is leaning more on his fastball, and it’s to his own detriment.

It’s always been the pitch that gets hit the hardest. In 2019 batters posted a .345 wOBA against his four-seam, last year .384, and this year .430. And yet, he’s continuing to throw it. Early in counts, late, whenever, it’s the lead pitch:

Compare that to last season, when the only time Plesac threw a four-seam first was a 3-0 count:

Now, this can’t be the only reason he’s struggling this season. But we’re talking about a four-seam that is ranked 560th out of 561 pitchers in Baseball Savant’s run value at 14. For context, Matt Harvey is at 559, Sam Hentges and his laser-straight fastball at 558, and Carlos Rodón leads the world with a -23 run value on his fastball. At 93 mph with nigh undetectable movement, it’s basically like he’s teeing it up for hitters half the time.

Plesac has other pitches that are good. His slider is a -10 by run value, the 14th best in the majors, his change is a 0, and his curve a -2.

I accept that pitchers need to throw fastballs to get along. It’s the pitch you throw to work the other stuff off. Even Zack Grienke throws a fastball 40% of the time, but that’s because he has like twelve other pitches that work off it. That’s the approach that you’d hope Plesac works his way back to for next season. His four-seam is … fine, and his command is sterling, he just needs to use the other stuff that makes it a better pitch.