If there has been a common theme in the Pirates' additions this winter, it's that they are probably in a pretty good spot if they can replicate their 2022 results.
Marco Gonzales was hurt and struggled for much of 2023, but in 2022 he tossed 183 innings with a 4.13 ERA. The rotation could certainly use someone like that. Rowdy Tellez tried to play through a forearm and finger injury and didn't come close to his 35-homer 2022 campaign.
And for Martín Pérez, it's the difference between an All-Star campaign and being booted out of a rotation.
Pérez and the Pirates are in agreement on a one-year, $8 million contract for 2024, pending a physical, lengthening out a rotation that desperately needs innings, in both quality and quantity. He provided both in 2022 for the Rangers, going 12-8 with a 2.89 ERA over 32 starts and 196 1/3 innings, earning him his first All-Star nod. While he had been a reliable inning eater for most of his career, that was the first time his ERA+ had been better than 100 since 2016. It was fair to wonder if it was an outlier year.
The Rangers were able to retain Pérez whenever he accepted his qualifying offer for the next season, but the results got much worse. His ERA inflated to 4.45, his FIP to 4.99 and he was booted out of the rotation for the final two months of the season. That bullpen experiment went reasonably well, so it could be a fallback in case Pérez doesn't regain his 2022 form, but the Pirates need a starter, not a reliever.
And when you look at those two seasons, the biggest difference is the effectiveness of the cutter.
Pérez leaned heavily on his two fastballs and a changeup early on in his career, often throwing his curveball and slider roughly 10% of the time each. That changed in 2019, when those breaking pitches took a backseat in favor of a new cutter. At its best, it is one of the best cutters in the game. At its worst, it gets hit hard and doesn't miss many bats. What's interesting is it is a real Jekyll and Hyde year by year. Here are his slugging percentages against the cutter each year, as well as the expected slugging percentages, which is based on batted ball, walk and strikeout data:
There were 84 pitchers who had at least 50 plate appearances end with a cutter in 2022, and Pérez had the 10th-lowest slugging percentage. In 2023, 106 pitchers hit that mile marker, and Pérez's slugging percentage allowed was the fifth-worst. Hitters went from a .228 batting average against it in 2022 to a .342 average in 2023. Going by Baseball Savant's run value, his cutter was worth 13 runs more than league average in 2022 and 13 runs less than average in 2023.
And the deeper you dive in, the uglier it gets.
Not only did hitters make hard contact (the average exit velocity went from 86.8 mph to 88.6mph), but hitters elevated it more. When Pérez is at his best, he's getting weak contact and ground balls. The cutter didn't yield nearly enough of either. Compare the launch angles of the hard contact he allowed in 2022 to 2023.
Here is 2022:
And here is 2023:
Every pitcher gives up some hard-hit contact, but in his All-Star campaign, it was mostly low line drives. Sure, those balls were still tagged and resulted in plenty of hits, but most of them were singles and just two were home runs. In 2023, not only did he allow more hard contact, but hitters were able to put it in the air, resulting in 10 home runs.
He also got fewer whiffs with the cutter. He relies on the sinker as his primary fastball, so he doesn't get a ton of strikeouts, but his strikeout rate dropped from 20.6% in 2022 to 15.3% in 2023. It's easy to see where those missing strikeouts were. His whiff rate with the cutter dropped from 17% to 11.7%, and his put away percentage (or the rate of two-strike pitches that result in a strikeout) was nearly halved, going from 27.5% to 14.3%. Pérez isn't going to strikeout a ton of hitters, but there's a big different between 7.8 K/9 and 5.9 K/9.
The cutter didn't have a significant change in spin, velocity or movement last year, so there's reason to believe he can get it closer to that 2022 form with some tweaks. It would also probably help if his sinker is sharper. Pérez's cutter is a vertical movement-driven pitch, which the sinker has more horizontal movement. They can tunnel off each other, and when he consistently lands the sinker on his hand side, like he did in 2022, it opens up those tunneling opportunities.
The sinker's results last year were pretty similar to what they were in 2022, but he didn't have the same command:
The sinker was all over the zone, especially in the middle. He got away with a lot of those errant pitches, but a misexecuted pitch can impact the entire sequence. If he isn't getting whiffs with the cutter, he doesn't have a strikeout pitch. If he isn't putting the sinker where he needs to, he's going to have less strikeout opportunities.
There's a good chance that Pérez's 2022 season winds up being his career year and he doesn't quite reach those highs again, but he can be more than just an inning eater. The Pirates needed another pitcher to go along with Mitch Keller and give a reliable five or six innings every time he touches the ball. He can do that, and they can be quality innings, too.
What remains to be seen is if the Pirates continue to add to the rotation.
