PORT ST. LUCIE — At least for the moment, the Mets are not planning to call in external reinforcements in the wake of Kodai Senga’s indefinite absence.

Even with standouts such as Blake Snell and Jordan Montgomery lurking as free agents, the Mets are not asking for an outside ace to step in.

Instead, “we’re asking people to step up,” president of baseball operations David Stearns said Thursday at Clover Park. “That’s what happens over the course of a baseball season.”

It has happened already, with Senga expected to open the season on the injured list with a moderate strain in his right shoulder.

Without their No. 1, the Mets will need a new No. 5 to join a group that is composed of Jose Quintana, Luis Severino, Sean Manaea and Adrian Houser.

The leading candidates — Tylor Megill, Joey Lucchesi and Jose Butto, who likely will get shots before the Mets’ group of untested prospects — all have major league experience, reason for belief and reason for caution.

All flashed promise last season, but in each case that promise followed disappointment.

Megill, invaluable rotation insurance at the start of 2022, held a 5.17 ERA 15 starts into last season.

His command disappeared, walking 12 in 17 ¹/₃ June innings, before a demotion to Triple-A Syracuse.

The righty tweaked his mechanics and was far better by the end of the season, finding both results and control for his final six starts, in which he posted a 2.55 ERA.

3

Megill — who joked the feeling and line of questioning felt familiar after he emerged from the outskirts of the rotation in 2022 to become the Opening Day starter because of injuries — said he hopes to get “back to throwing a lot of strikes.”

If he is able, Megill might be the top choice of the group, particularly because of a new weapon.

The 28-year-old debuted a splitter in his last start of last season, an offering he spent the offseason honing. He picked up the diving pitch from Senga, and instead of a ghost forkball, Megill’s is branded the “American spork.”

“Thanks, Kodai,” Megill said with a smile. “Got a lot of reps with it and it’s working well. … It’s definitely part of the arsenal now.”

Megill was dominant at the onset of the 2022 season, filling in for Jacob deGrom and displaying upper-90s heat that might have led to biceps and shoulder issues. Megill suggested he is no longer trying to blow hitters away.

“The main thing is sustain the velo throughout the whole game,” said Megill, who said his fastball is sitting 94-96 mph in the early days of camp.

If not Megill, Lucchesi could win the job after a strange 2023 campaign.

The lefty was excellent in the majors — finishing with a 2.89 ERA in nine starts at the beginning and end of the season — but struggled at Triple-A, citing the automated strike zone that presented a problem.

The lefty has returned this spring noticeably trimmer and said he dropped nine pounds this offseason.

“Feel better, my energy levels are better,” said Lucchesi, who dropped fat and now wants to add muscle that might help his velocity grow. “I wanted to be more cut. I was a little chubby — wanted to look more like an athlete.”

3

Lucchesi’s strong September last season included seven innings of one-run ball (unearned) against the pennant-winning Diamondbacks, an outing that particularly helped his mindset.

“The confidence in knowing I’m an elite pitcher and I can do this,” Lucchesi said. “If I perform like how I know I can do, I think I’ve got a shot at getting [the fifth spot].”

Like Lucchesi, Butto was solid (3.64 ERA) in the majors last season but rough (5.93 ERA) with Syracuse.

The righty was used primarily for spot starts until a strong September, when opportunity and a new sinker helped him finish the season with five strong starts.

The 25-year-old also will try to mount an argument for the final rotation spot that can be won with an impressive spring.

“They compete,” manager Carlos Mendoza said of the trio. “Their ability to get outs [stands out]. We got few guys that can do that.”