Mets Move Kodai Senga To Bullpen

The Mets are moving struggling right-hander Kodai Senga from the rotation to the bullpen, manager Carlos Mendoza announced to reporters this morning (via ESPN’s Jorge Castillo).

Senga’s move to relief work is the latest development in what’s been a nightmare calendar year for the former NL Rookie of the Year runner-up. The now-33-year-old righty got out to a brilliant start in 2025 (1.47 ERA through 13 starts) before a mid-June hamstring strain sent him to the injured list. It seemed innocuous enough at the time, but Senga has been a shell of himself since returning.

In his final 39 2/3 innings last summer, Senga pitched to a 5.90 ERA. His struggles were so pronounced that he eventually consented to being optioned to Triple-A Syracuse in hopes of getting back on track. That didn’t happen, and Senga didn’t pitch in the majors after Aug. 31.

The 2026 season started out in promising fashion. Senga was dominant in spring training, and his first two starts this season produced a 3.09 ERA (four runs in 11 2/3 innings) with a 16-to-5 K/BB ratio. He looked to have put that awful conclusion to the 2025 season in the rearview mirror.

Disaster has since struck a second time. Senga was annihilated for 16 earned runs over just 8 1/3 innings across his next three starts. The Mets placed him on the 15-day injured list due to a lumbar injury, and he wound up missing nearly two months. In two starts since returning, Senga has surrendered 11 runs in 7 2/3 innings. All told, he’s followed up that pair of brilliant early-season starts with 27 earned runs in 16 innings (15.19 ERA), a staggering nine homers allowed (5.06 HR/9), and nearly as many walks (17) as strikeouts recorded (18).

Over the past calendar year, Senga’s 7.62 ERA is the worst among the 332 pitchers who’ve tossed 50 or more innings. His 14.2% walk rate is the sixth-worst in that same group, while his average of 2.27 homers per nine innings pitched is fifth-worst. Relievers Ryan Rolison and Kevin Kelly are the only two pitchers who’ve seen a greater percentage of their fly-balls turn into home runs than Senga (21.5%).

Senga is in year four of a five-year, $75MM contract that paid him a $5MM signing bonus and annual salaries of $14MM. It’s hard to fathom just how precipitously his stock has plummeted over the past calendar year. The Mets have little choice for now but to try to get him back on track. They’re on the hook for that salary regardless, but if his struggles persist in the bullpen, they’ll have to contemplate moving on altogether.

In the meantime, they’ll lean on Nolan McLean, Freddy Peralta, David Peterson and Sean Manaea in the rotation. Manaea has recently gotten back on track after a terrible start to his season, but Peterson has struggled for the majority of the 2026 campaign while Peralta has run into hard times of late. He was blown up for 10 runs in his most recent outing and surrendered six runs in a different start earlier this month. That pair of shellackings has inflated Peralta’s ERA all the way from 3.53 to 4.83.

With Christian Scott and Clay Holmes on the injured list, options to round out the rotation are sparse. Touted young righty Jonah Tong was a consensus top-100 prospect this time a year ago, but he’s been hit hard in 28 2/3 major league innings and has been shelled for a 6.30 ERA in Triple-A this season. Southpaw Zach Thornton has better numbers than Tong in Syracuse, but the 24-year-old was hit hard in his own big league debut earlier this year. Swingman Tobias Myers hasn’t pitched more than 2 1/3 innings in nearly two months, and he’s given up runs in seven of his past eight appearances — a total of 16 in his past 11 1/3 frames (12.71 ERA).