2 NY Mets players whose late collapse is a red flag moving forward, 2 whose isn't

The New York Mets’ 2025 season will go down as one of the franchise’s most notorious second-half collapses. On August 1, they were firmly in the second Wild Card spot and only a half-game out of the division. The Mets struggled badly, especially in September, and were eliminated from a playoff spot on the last day of the season. Needless to say, many of their players down the line, with these four in particular showing the biggest red flags. However, not all of them had as worrying second halves as their surface numbers may suggest.

Jeff McNeil’s September was a red flag

Jeff McNeil returned to the club in late April and looked well on his way to a bounce-back season. His first 378 plate appearances saw him bat .256/.348/.451 with a .343 wOBA, and 124 wRC+. He was hitting for more power than ever before, with a dozen home runs and a .194 isolated slugging percentage. The utility man struck out at a microscopic 10.8% rate, while drawing walks at the same pace.

But September proved to be an extremely rough month for McNeil. It was only 84 plate appearances, but he hit .187/.274/.240 with a .239 wOBA, and 53 wRC+. While he kept up a solid 9.5% walk rate, his strikeout rate climbed to 16.7%. The power he showed earlier this season had dissipated, with a sub-.100 ISO at .093, and no home runs.

However, what is worrying is how McNeil got exposed at the plate. McNeil saw seven pitches at least 5% of the time this season. His whiff rate on sliders at 26.8% was the highest among all of the pitches he saw. From his first game of the season through the end of August, he saw sliders 21.2% of the time. But in September, he saw a slider 25.3% of the time. Meanwhile, he was most effective against sinkers, with only a 12.4% whiff rate and .383 xwOBA. Up through August, he saw a sinker 14.3% of the time, but in September, that fell to only 11.9%.

McNeil’s overall whiff rate in September climbed to 22.6%, compared to just 12.7% in 2025 prior to that. McNeil changed his approach this year to take advantage of his pull-side power. But it seems like opposing pitchers figured him out in September. That means the ball is back in McNeil’s court, and it’s up to him to adjust. 

Kodai Senga’s late-season collapse should set off warning signals

2025 was Kodia Senga’s first semi-healthy season after missing most of 2024 due to shoulder problems. Heading into August, Senga looked like he could win Comeback Player of the Year. Throughout his first 85 innings, Senga had a 2.00 ERA, 3.75 FIP, and 1.21 WHIP. He was striking out batters at an above-average 23.4% rate, but had a mediocre 11.7% walk rate. But he excelled at limiting home runs and hard contact, with a 0.74 HR/9, 88.2 MPH exit velocity, and 7% barrel rate. 

But Senga would only pitch 27.2 more innings after the end of July. In that time, he allowed 19 earned runs, only struck out 20.6% of opponents with a sub-par 10.7% walk rate, and was giving up far more home runs and hard contact. This time, Senga was nailed for a 1.63 HR/9, 90.3 MPH exit velocity, and 10.2% barrel rate. Things got so bad for Senga that the Mets sent him to Triple-A at the start of September to figure things out.

The red flags for Senga’s second-half collapse started at the beginning of the year. Senga’s four-seam fastball velocity came in at 94.7 MPH, both prior to his mid-June injury and after it. His fastball also lost movement, and it resulted in a much less effective pitch. In 2023, opponents had a .244 BA, .399 SLG%, and .338 wOBA vs his fastball. This year, they batted .279 with a .543 SLG% and .391 wOBA. Even Senga’s signature ghost-fork was less effective. A .210 xwOBA and 41.8% whiff rate are both still elite, but a step back from the .182 xwOBA and 59.5% whiff rate he had on the same pitch in 2023. His Stuff+ came in at just 95 for the season, a significant drop from 101 in his 2023 rookie campaign. His 2.00 ERA and 3.75 FIP weren’t as good as they looked, either. He had a 4.47 SIERA and 4.28 xFIP. During August, he had a 4.65 SIERA and 4.59 xFIP. It also seemed Senga fooled fewer batters. His out-of-zone swing rate in April-July was 29.4%, but fell to 26.7% in August.

Senga will be another year removed from shoulder issues in 2026, but it will be his age-33 season. Hopefully for his sake and the Mets’ sake, this was his way of fully recovering after nearly missing an entire season. However, given his age and decline in overall performance, one has to question if his August was only a sign of things to come.

David Peterson’s second half likely isn’t sustainable

David Peterson followed up his very promising 2024 season by making the All-Star game in 2025. By the end of July, Peterson had a 2.83 ERA, 3.38 FIP, and 1.25 WHIP over 121 innings pitched. Peterson only had a 20.1% K%, but a solid 8.2% walk rate and an outstanding 0.52 HR/9 ratio. Peterson avoided quality contact well, as evidenced by his home run rate, along with his 5.9% barrel percentage. 

But the rest of the season did not go well for Peterson. He had a 7.74 ERA while walking 10.9% of opponents. His HR/9 also got slightly worse, rising to 0.76, and his barrel rate climbed to 7.5%. Peterson’s ERA on the season, which once sat below 3.00, ended at 4.22. However, that’s about where the negatives end for Peterson’s second half. There were far more positives than his surface numbers might suggest.

Peterson’s 4.29 SIERA and 3.88 xFIP were much better than his ERA, which was approaching 8.00. Plus, they weren’t that much worse than the 4.00 SIERA and 3.66 xFIP he had through the first four months of his season, and almost identical to the 3.88 xFIP and 4.20 SIERA he had from his first start of 2024, through the end of July 2025. His .366 batting average on balls in play and 53.1% left on base rate are both indicators of some bad luck at play, compared to the .313 BABIP and 72.7% LOB rate of his career. Peterson’s stuff and execution got better, with an 89 Stuff+ and 101 Location+ through the end of July, and a 92 Stuff+ and 105 Location+ in August and September. He was fooling batters more frequently as well. Batters swung outside the zone 28.5% of the time with a 22% whiff rate when facing Peterson in his first 20 starts of the year. They had a 32.1% out-of-zone swing rate and 22.2% whiff rate during August and September vs Peterson.

Plus, what sample size is more reliable? The 41 starts and 242 innings where Peterson had a 2.86 ERA, or the ten starts and 47.2 innings where he struggled? Peterson’s final months of the 2025 season should be one of the Mets’ lesser concerns heading into the offseason. Sure, him struggling was a reason the Mets fell off down the line, but it’s nothing the Mets should fret over this offseason.

Sean Manaea still has gas left in the tank

The Mets re-signed Sean Manaea to a three-year contract last offseason after he became a rotation anchor in 2024. However, an oblique strain plus a setback led to Manaea not making his 2025 debut until July 13. When he made his way back to the mound, he looked like he was picking up where he left off. Through his first 17.1 innings and four appearances, Manaea only allowed four earned runs with 22 K’s and four walks.

Manaea would end up pitching 43.1 more innings from the start of August onwards, but the results were definitely not pretty. The veteran left-hander owned a 7.06 ERA, 4.96 FIP, and 1.36 WHIP. Most of his struggles can be traced back to the long ball. Manaea allowed 2.28 home runs per nine innings on average while having an unimpressive 9.4% barrel rate and 90.7 MPH exit velocity.

So what’s the difference between Manaea and Senga? After all, Manea is a year older, also struggled to stay healthy, and arguably struggled just as severely as Senga did. The first thing is that Manaea’s pitch quality is still good. Stuff+ pinned him at 103 in August and September, a step forward from the 98 mark he had in 2024. Manaea was still fooling opponents, with an out-of-zone swing rate of 31.1% and an overall whiff rate of 24.9%. His 23.1% K%-BB% was the 11th best in baseball among all pitchers with at least 40 frames during the final two months of the season, and tied with likely AL Cy Young winner Tarik Skubal. Overall, he had a 27.2% strikeout rate and a 4.1% walk rate. Other numbers point to this being a small sample size fluke. Manaea may have been home run-prone, but that’s not an oddity for his career. His 22% HR:FB ratio is likely unsustainable over a larger sample size, as indicated by his career 12.9% ratio. He had both a 3.50 SIERA and 3.59 xFIP during the final two months of 2025. 

Many of Manaea’s struggles can be chalked up to a small sample size, where his numbers would likely come back down to Earth if he played more. A typical offseason and Spring Training should be all Manaea needs to get back into the groove in 2026. He should definitely be given another chance with the Mets next year in their starting rotation.