NY Mets pitcher coming off of career-year is poised for regression

Last season, David Peterson well exceeded expectations for the New York Mets as he put together a career year that gave hope that he could be a staple in the 2025 rotation and beyond. While the Mets have been busy rebuilding the starting rotation, reuniting with Sean Manaea, and adding three new arms to the mix, Peterson is a lock and someone the Mets will be counting on.

It's easy to look at Peterson's sparkling 2.90 ERA in 2024 and believe that the big lefty who struggled mightily in 2023 has finally arrived and become the pitcher the Mets were hoping for when they drafted him in the first round back in 2017.

A deeper dive into the numbers however shows that Peterson is a prime regression candidate in 2025. How far that regression will go is up for debate, however, several factors make it clear that he simply isn't a sub-3 ERA hurler.

These factors prove Peterson's performance will regress for the Mets in 2025

The first question that Peterson will have to answer is whether or not he can hold up over a full starter's workload this season. Throughout his career, he's shuffled back and forth a bit from both the rotation to the bullpen and the Majors to the Minors. 2024 saw him reach career highs in both starts made, 21, and innings pitched, 121, both of which are just about two-thirds of an average starter's workload.

Typically, pitchers tend to see diminishing returns the more their workload increases, and that certainly could be the case for Peterson, especially given the other question marks in the rotation may mean the Mets will need to lean on him even more should things not break right with their projects in Montas and Holmes.

More concerning is the drastic reduction in his strikeout rate. As a starter in 2023, Peterson struck out 10.49 batters per nine innings. Last season, that number plummeted to 7.51 K/9.

The drop in strikeouts might be less alarming if it corresponded with a marked shift in batted ball data, however, Peterson's contact rates didn't vary much from his career averages.

He's always generated ground balls at a high level, 50.1% last season and 50.3% for his career, but the single greatest change for Peterson is that fewer flyballs he gave up left the yard. Owner of a career 14.6% HR/FB ratio, that number was halved in 2024 dropping to 7.8%.

Fewer home runs is a good thing, for sure, but it doesn't seem sustainable based on the data. Looking at average exit velocity, it's clear that there was no significant change with his career rate being 89.5 MPH, and his 2024 rate sitting at 89.3 MPH. Launch angle tells a similar story with the numbers sitting at 8.0 degrees for his career and 7.2 degrees in 2024. The same holds true for barrels, a measure of how often batters make contact with the sweet spot, as his barrel percentage in 2024 was 7.3% versus a career mark of 7.9%.

Further illustrating the story, his hard-hit rate (42.7%) in 2024 was a hair higher than his career mark (41.6%). He also gave up slightly more flyballs than normal (29.2% versus 28.2%), few of them wound up in places where they could do damage.

This confluence of factors paints a picture of a pitcher who was more lucky than good in 2024. Metrics like expected ERA (4.58), FIP (3.67), and xFIP (4.10) all bear that out. Simply put, the peripherals bear out that his performance on things solely within his control did not match his results.

Lastly, the disagreement between those peripheral metrics is cause for some concern. If he pitches to a 3.67 ERA like his FIP suggests he'll be a fine starter even with some regression. If it's a 4.10 mark like his xFIP says, his regression would put him as a capable back-end starter. If it's a 4.58 performance, expect to see one of Griffin Canning, Jose Butto, Tylor Megill, or Paul Blackburn cut into his opportunities.