As the 2025 Mets devolved from a team with World Series hopes to one that missed the playoffs, the main culprit behind their fall was the pitching -- the starting rotation specifically.
Among the issues?
The season-ending injuries suffered by Griffin Canning and Tylor Megill in June, the summer struggles of Sean Manaea and Kodai Senga, and the transition from reliever to starter that led to truncated starts by Clay Holmes.
When it comes toDavid Peterson, it was a tale of two seasons.
The left-hander charged out of the gate and maintained his excellence through Aug. 1, earning his first All-Star nod along the way.
Things changed after that, with Peterson regressing to the point where he wasn't a serious consideration to start the Mets' final game of the season against the Marlins in Miami, which he was on regular rest for.
Peterson is arbitration-eligible for the final time ahead of 2026, and will be set for free agency after the season.
Should he be part of the Mets' starting rotation calculus, or is it time for New York to explore a trade?
WHY IT COULD MAKE SENSE TO TRADE PETERSON
The last nine starts of Peterson's season were alarmingly bad, as he posted an 8.42 ERA while allowing 52 hits in 41.2 innings.
If you include just the last five starts, he had a 12.54 ERA while allowing 33 hits in 18.2 innings.
The ERA cited above is a inflated a bit due to the clunker Peterson had on Sept. 23, when he surrendered five runs on five hits in just 1.1 innings against the Cubs in Chicago. That was his last appearance of the season.
Peterson's issues down the stretch were shocking after the way he pitched over the first four months (when he posted a 2.83 ERA), but they were also a reminder that he has never put together back-to-back strong seasons.
Here's Peterson's ERA by year:
2020: 3.44
2021: 5.54
2022: 3.83
2023: 5.03
2024: 2.90
2025: 4.22
Peterson also hasn't been an innings-eater, with the 168.2 frames he threw in 2025 being the highest total of his career by far.
Before this past season, Peterson's previous high was 121.0.
WHY IT COULD MAKE SENSE TO KEEP PETERSON
While the last few months of Peterson's season were unsightly, there's reason to believe he was also the recipient of bad luck on balls in play.
Peterson's ERA over his final nine starts was 8.42, but his FIP was 3.88 -- suggesting that lots of bounces did not go his way and that poor defense behind him played a part.
It's also fair to wonder whether the innings increase was partially to blame for how poorly he performed in August and September, with Peterson's downturn going pretty much hand-in-hand with him passing his previous career high for innings in a season.
There's also Peterson's contract status to take into account.
With Peterson entering his final season of arbitration, his expected salary is $7.6 million. That means he is low-risk, high-reward.
In the event Peterson struggles, he can easily be replaced without the Mets having to think too hard about it. One way or the other, there is no commitment beyond 2026.
Health should also be considered here.
Unlike Manaea and Senga, Peterson -- whose last major injury came in 2023 and resulted in offseason hip surgery -- made 30 starts in 2025 as he took the ball every turn without issue.
VERDICT
I theorized the following in our stay or go piece revolving around Senga:
Using logic and deductive reasoning, it's fair to believe that three pitchers might be penciled in right now as members of the Mets' 2026 rotation: Holmes, Manaea, and Nolan McLean.
That would leave room for two (or three, if the Mets use a six-man rotation) other members of the starting staff.
As the front office factors in the other young starters (Brandon Sproat and Jonah Tong), they'll likely also add one, if not two, members to the rotation externally -- with a trade arguably being the most sensible way to import a top of the rotation starter.
But even with New York potentially having lots of options, they learned the hard way this past season that you can truly never have enough starting pitching.
In a world where the Mets are pitching-rich and feel comfortable, they can always explore a trade of Peterson during the 2026 season. They could also utilize him in relief, where he excelled during the 2024 postseason. Or perhaps he's just good and needed and sticks in the rotation.
That's why it should be an easy call to retain Peterson this offseason, whether the team envisions him beginning the year in the rotation or not.