PORT ST. LUCIE, Fla. -- The Mets endured their first injury scare of 2024 on Wednesday when Kodai Senga skipped the team’s workout due to what manager Carlos Mendoza termed “overall arm fatigue.” Senga was due to undergo testing Wednesday afternoon, according to a person with knowledge of the situation, and the Mets hope to know more soon.

“After his side session yesterday, he came in and experienced some arm fatigue,” Mendoza said. “So he stayed inside, and we’re taking a look at him.”

Senga was unavailable to speak on his condition Wednesday because he was receiving treatment, according to a team spokesman, who added that club officials wanted to refrain from speculating publicly before receiving all the facts. One person close to Senga said he had reason to consider the issue minor, but added that Senga can be difficult to read.

There is no more important member of the Mets’ rotation than Senga, who went 12-7 with a 2.98 ERA last season and made the National League All-Star team as a rookie. With Max Scherzer and Justin Verlander out of the picture, Senga entered this spring as the Mets’ unquestioned ace.

The team has taken pains to keep Senga healthy since signing him to a five-year, $75 million contract in late 2022. Last season, the Mets made it so Senga made all but three of his 29 starts on five or more days rest, taking advantage of team off days and sometimes adding a sixth starter or shuffling other rotation members to accommodate him. In that way, the Mets hoped to mimic a traditional Japanese once-per-week pitching schedule.

Senga finished with 166 1/3 innings, a number he had eclipsed just twice over 11 seasons in Japan.

If Senga misses time, Tylor Megill is the likely next man up in the rotation given his strong finish to last season. But he will have competition for the job; Mets officials are proud of the rotation depth group they have assembled, including Joey Lucchesi, José Butto and Max Kranick. Prospects Mike Vasil, Christian Scott and Dominic Hamel are also edging closer to the Majors.

“We have a lot of names,” Mendoza said.