Sean Manaea's Failure To Make Mets' Rotation Could Be Beginning of the End

[Matthew Nethercott]

Image courtesy of © Rhona Wise-Imagn Images

At long last, Opening Day is right around the corner. However, one of the New York Mets' biggest question marks coming into spring training remains unanswered at the dawn of the season, and that is Sean Manaea.

Manaea signed with the Mets ahead of the 2024 season and immediately transformed his profile by adopting a lower arm slot and a cross-body delivery inspired by Chris Sale. This mechanical overhaul led to a career-best 3.47 ERA over 181.2 innings, fueled by a sinker that jumped to 92.4 mph on average.

According to Baseball Savant, his primary four-seamer posted a .218 xBA, while his sweeper became a legitimate put-away pitch with a 33% whiff rate. By the end of 2024, his Pitching Run Value sat in the 88th percentile, making him the undisputed anchor of the Mets' rotation during their postseason push.

Sean Manaea's 2025 and 2026 Spring Struggles

However, the 2025 season saw those gains evaporate, as Manaea regressed to a 5.64 ERA and a 1.22 WHIP across just 60.2 innings. The decline was largely attributed to a right oblique strain suffered early in camp, followed by the discovery of a loose body in his left elbow that sidelined him until July.

The advanced metrics highlighted a thinning arsenal. His fastball velocity dipped to 91.7 mph, and his hard-hit rate ballooned to 42.6%. Though he avoided surgery in the offseason, his xERA finished at a middling 4.02, suggesting his poor results weren't merely a mirage or sign of bad luck.

Entering 2026 spring training, the alarm bells have shifted from his health to his radar gun readings. In his most recent Grapefruit League outings, Manaea has averaged a meager 88.3 mph on his four-seamer -- a significant 4 mph drop from his 2024 peak -- and has yet to touch 90 mph this spring. While he and manager Carlos Mendoza have publicly downplayed the dip, citing a transition to a new cutter and mechanical tweaks to his arm slot, the lack of zip on his pitches is undeniable. In a recent four-inning perfect performance against the Marlins, the southpaw generated only one swing-and-miss, raising serious questions about whether he can survive the regular season with a heater that currently sits in the high-80s.

Sean Manaea fired off 4 perfect innings today with 4 K

While the results were good, the pitch data is very concerning. He averaged 88 MPH on his fastball, nearly 4 MPH slower than last season. So, uhhhhhhhh pic.twitter.com/6GuZUSH8a7

— Thomas Nestico (@TJStats) March 17, 2026

Manaea's Future In the Mets' Rotation

This weekend, Mendoza announced that Manaea will not start the season in the rotation. As it sits now, the starting five is comprised of:

1. RHP Freddy Peralta
2. LHP David Peterson
3. RHP Nolan McLean
4. RHP Clay Holmes
5. RHP Kodai Senga

Manaea will begin the season in a piggyback role in the bullpen. This is most likely not permanent and only through the first two rotation turns, but it should be noted that the Mets have some concern with how Manaea has performed this spring.

"I'm not concerned, as long as he keeps telling us that he's healthy," Mendoza said earlier in camp. "That's what he keeps telling us: 'I feel great.' Look, it might take a while for the velocity to come back. That's why he's tinkering with the cutter, the changeup is good, the sweeper."

"I feel healthy, I feel good. To me, I'm not concerned about anything." Manaea said after his outing against the Cardinals on March 12. He added that adrenaline will become a factor during regular-season games and might boost his velocity.

Mendoza did claim that Manaea will make starts for the 2026 Mets, but how many remains to be seen. At 34 years old, his margin for error has evaporated; without tangible improvements to his health and stuff, Manaea could become dead weight on an already-bloated payroll.

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