David Peterson went 9-6 with a 4.22 ERA across 168 2/3 innings in 2025. He struck out 150 batters holding a 20.7% K rate. His pitch repertoire consisted of a sinker, which he threw 29% of the time, a fastball at 23%, a slider at 19%, a changeup at 15%, and a curveball at 14%. Peterson pitched well from March through July, positing a remarkable 1.05 ERA in July, 2.30 ERA in May, and a solid 3.06 ERA in March and April.
However, from August on, there was a different story. Peterson’s ERA skyrocketed to a 6.68 ERA in August then ballooned to an incredible 9.72 in September and October. An interesting statistic that seemed to coincide with his ERA numbers was his ground-ball percentage.
For 2025, Peterson compiled a 54.7% ground-ball rate. This means that more than half of the contacts made from his pitches resulted in ground-balls. This placed Peterson seventh in the entire Major Leagues. He also recorded 205 outs from ground balls, placing him at eighth in the league. Having a higher ground-ball percentage is a good statistic to have because it is keeping the ball in the ball pack. As they say, “you can’t hit a ground-ball out of the stadium.”
While Peterson found success by throwing to contact to induce ground balls, it can come as no surprise that when Peterson struggled, his ground-ball rate went down. In the months of September and October, when Peterson’s ERA was the highest at 9.72, his ground-ball rate was the lowest at 50%. In the month of August, when Peterson posted a 6.68 ERA, he also posted his third-worst ground-ball rate. In the months of September and October, there was a correlation that when his ground-ball rate went down, his hits against went up.
In those months, Peterson gave up 25 hits over the course of 16 2/3 innings in the four games he pitched. That is an average of more than six hits per game and more than a hit per inning. Peterson still relied heavily on his sinker throughout the year, however, his use of his fastball was significantly lower in his worst months of September and October compared to his best month of July.
It really was a tale of two halves for Peterson. He enjoyed success up until August where he hit a wall. It will be interesting to see what plan Mets new pitching coach Justin Willard comes up with for Peterson. Peterson still has a lot of potential which was displayed in the earlier part of the season, now how can he sustain that for an entire season. Peterson could be a pillar in the middle of this Mets rotation barring he can maintain his success for the entirety of 2026.
