The New York Mets have some questions in their bullpen. I recently wrote about how the Mets don’t have a trustworthy lefty in the bullpen or rotation, but they have guys with reverse splits who are effective at getting left-handed hitters out. They have another internal option.
David Peterson reminds of Drew Pomeranz: he didn’t perform as a starter, but is a perfect candidate to move to the bullpen.
For those who aren’t familiar with Drew Pomeranz, he’s a relief pitcher for the San Diego Padres. Early in his career, Pomeranz was mostly used as a starter, making 140 starts in The Show. In 2019, he was struggling in the San Francisco Giants rotation with a 5.68 ERA, 1.61 WHIP, and 74 ERA+ (26% below average) in 17 starts. Then the Giants traded him to the Brewers, where his career would change drastically.
The Brewers saw that Pomeranz was throwing five pitches, but three of them weren’t working. He threw his last changeup in San Francisco, and abandoned his cutter within the first month in Milwaukee. His sinker basically disappeared too, since he threw it less than 5% of the time in the second half of 2019 and didn’t bring it back in 2020. After scrapping those three pitches and moving to the bullpen, his average fastball velocity rose over three miles per hour (from 91.8 to 95.1 mph) and spin rates rose slightly too. Over 25 relief appearances for the Brew Crew, he posted a 2.39 ERA, 0.91 WHIP, and 188 ERA+.
To this day, Pomeranz is a two-pitch pitcher. He throws fastballs up in the zone and curveballs down. Since switching to the bullpen full-time, his ERA is 1.86. That’s good, to put it mildly.
So how can David Peterson replicate this?
Similar to Pomeranz, Peterson’s best pitch is his fastball. It had a -3 run value in 2021 (negative numbers are good for run value) and a -6 in 2020. Hitters hit just .221 off his fastball, with a slugging percentage of .382. He should keep using his fastball the same way he has been.
In 2020, his slider was excellent with a run value of -6. Hitters hit just .119 with a slugging percentage of .254 and an xwOBA of .216 against it. In 2021, righties rocked it to a run value of 5 while hitting .333 and slugging .758 against it. It was still effective against lefties, who hit .265 and slugged just .353 against it. His slider had slightly more spin and velocity in 2021, which are generally good things, but the main issue for Peterson is control, or more accurately lack thereof.
Peterson had a WHIP of 1.40 in 2021 after walking 29 batters in 66.2 innings, which is a BB/9 of 3.9. He was in the 25th percentile of walk rate on Baseball Savant, after walking 10% of all batters he faced. That’s way too much traffic on the bases, especially when you give up a hit per inning. Looking at his heat maps, his pitches are mostly either down the middle or a ball, with one exception: his changeup.
His changeup was his second best pitch in 2021, with a run value of +1 (just slightly below average). It had excellent horizontal movement, averaging 17.6 inches of break, which is 4.3 inches more than average. As mentioned above, it was also the pitch he had the most command over, with a consistent grouping at the bottom of the zone or just slightly below. It’s been very effective vs. right-handed hitters, who hit just .200 and slugged .325 against it.
So my proposal is this: David Peterson should ditch his sinker and curveball, and move to the bullpen.
Everybody crushed his sinker (.274 batting average and .507 slugging overall) and he barely throws his curveball anyway (0.6% of all of his pitches in 2021), so get rid of them. He can throw his fastball to both righties and lefties, and then he has his changeup against righties only and his slider against lefties only. He would essentially become a two-pitch pitcher, with his secondary pitch varying by hitter handedness.
Similar to Pomeranz, his velocity and spin rates will benefit from moving to the bullpen. Right now, he has to attempt to spread out his energy over a full start. If he can come in for one inning and let it rip, he’ll benefit more. His fastball already averages 92.6 miles per hour. He might consistently sit around 96 in a bullpen role, topping out higher.
We’ve seen many pitchers who failed as starters move to the bullpen and have success. Drew Pomeranz, Wade Davis, and Josh Hader are just a few who come to mind. There’s no reason David Peterson can’t be the next big lefty reliever.