PORT ST. LUCIE, Fla. — In these opening days of spring training, the Mets are exactly where any $300 million team expects to be: facing few questions about the makeup of their roster.

The lineup is set. The rotation is mostly set. There are a couple of bullpen spots and maybe a bench gig up for grabs, but other than that, the Mets already pretty much know who they’ll take to Houston for the March 27 opener and beyond.

On the periphery, though, there are plenty of uncertainties — role changes and new positions and leftover injuries. Here is all the roster-related news and notes from manager Carlos Mendoza’s first news conference of camp Tuesday:

Who’s on second?

Jeff McNeil — probably.

Mendoza hedged on the question of whether McNeil is the no-doubt starter, saying that he is “going to play a huge role” and “get a lot of opportunities” for the Mets in 2025. But Mendoza also mentioned Brett Baty, Luisangel Acuna and recently signed utility infielder Nick Madrigal (and prospect Jett Williams) among those who also will get chances at second during camp.

So McNeil almost surely will be the second baseman to start, but if he gets off to another slow start, the Mets have options.

“Look, Jeff McNeil is coming into camp here with an opportunity to be the second baseman,” Mendoza said. “There’s competition but Jeff is pretty much right there. He’s a big part of this team . . . The good thing with Jeff is he provides versatility. So you can move him around everywhere.”

Around the horn

Elsewhere on the infield, Acuna (third base for the first time ever) and Madrigal (shortstop for the first time since he was a college sophomore in 2017) are going to try new positions.

For Acuna, it’s about continuing to expand his versatility and give the Mets options. They liked what they saw in his taste of the majors in September, so the more ways they can fit him onto the roster (at some point during the season), the better.

For Madrigal, it’s about solidifying the last bench spot. He lines up as the favorite. The Mets don’t have a backup to Francisco Lindor, though, so if Madrigal proves capable enough, he can do that.

Baty, meanwhile, will play second base in addition to his usual third. The Mets started that experiment after demoting him to Triple-A Syracuse last year. Barring injury, he doesn’t have an obvious path to an Opening Day roster spot.

“We want to see [Baty at second] ourselves,” Mendoza said. “This is a guy who’s willing to do whatever it takes to make this club. He’s been very vocal about it in some of the conversations, whether it’s with [president of baseball operations David Stearns] or myself through the offseason where it’s like, ‘We probably need you to play multiple positions,’ and he’s up for it. Now he’s got to go out there and compete and do it and be himself because he is a really good player.”

Pitching plans

With the Mets intending to deploy a six-man rotation most of the time, Mendoza mentioned three guys competing for that No. 6 slot: Griffin Canning, Paul Blackburn and Tylor Megill.

Noticeably not included was Jose Butto, who will work strictly as a reliever, Mendoza said. That all but locks up another bullpen spot (since Butto cannot be optioned to the minors).

“We just felt it was best for him and the team to keep him in that role as a multi-inning guy — that 40-to-45 range for pitches,” Mendoza said.

Megill may be at a disadvantage in the rotation battle, if only because he still can be sent to the minors. Canning and Blackburn cannot, so the Mets may well keep one in the rotation and use the other as a long man out of the bullpen.

“If everyone is healthy, there’s going to be some tough conversations and tough decisions,” Mendoza said.

Canning said: “That’s all you can ask. Competition brings out the best in guys.”

Injured, sort of

Among the Mets coming off surgery…

* Lefthanded reliever A.J. Minter, who had left hip surgery in August, won’t throw his first bullpen session until late February. The Mets intend for him to be ready to start the season, but he isn’t a lock.

* Blackburn is “maybe a little bit behind,” Mendoza said, but he, too, is expected “to be fully built up by the time we break camp.” He had surgery to repair a spinal fluid leak in October.

* Infielder Ronny Mauricio won’t play in exhibition games until mid-March. He has been out of action since tearing the ACL in his right knee in December 2023, the recovery from which has been complicated and slow.

What about Starling Marte?

With Juan Soto in rightfield virtually every day and Jesse Winker at DH most days, Marte seemingly won’t get consistent at-bats. That would be a big change for a $19.5-million-per-year player who has been a regular when healthy.

“When he’s healthy, he’s an impactful player,” Mendoza said. “The reps in right field will be limited, for obvious reasons. Those are the conversations I’ll continue to have with him, whether it’s DH with him and Jesse. If he doesn’t see his name in the starting lineup, he might get the biggest at-bat of a game, and he’s got to be ready for it. He’s got a huge role on this team. We’ve just got to keep him healthy.”