PORT ST. LUCIE — The way baseball usually works, injuries end debates.

By the end of Mets camp, roster spots that seem filled today might not be, and competitions among fringe roster members may be decided by who remains off the injured list.

Already, there are (slight, at the moment) injury concerns involving infielders Jeff McNeil and Joey Wendle that could create additional Opening Day roster spots should the pains linger.

But for the purposes of today, assume the Mets leave camp with clean bills of health from their position players. Which bench spots would be up for grabs?

Every position appears set apart from third base, where Brett Baty is the clubhouse leader over Mark Vientos through the first week of Grapefruit League play.

Contracts and experience dictate Omar Narváez will be the backup catcher, Tyrone Taylor the fourth outfielder and Wendle (health permitting) a backup, flexible infielder.

That would leave two spots available from a group that includes Vientos, DJ Stewart, Zack Short, early camp standout Trayce Thompson and non-roster sluggers such as Luke Voit and Ji-Man Choi.

The competition is ongoing, Carlos Mendoza said.

“We’re still a few weeks away, see how camp unfolds,” the manager said before a rain-shortened, 5-2 loss to the Astros that was called with one out in the top of the sixth at Clover Park. “It’s too early to tell [the bench spots].”

Vientos is a leading candidate for DH reps after crushing pitching at Triple-A last year but has yet to prove he can hit major league pitching.

The righty hitter who has crushed lefties in the minors is 3-for-15 with a home run in the early days of the Grapefruit League.

The lefty-hitting Stewart could be Vientos’ DH complement (or a bench bat) after emerging during last year’s second half and demolishing righty pitching.

But Stewart (and Vientos) notably can still be optioned to the minor leagues, which could persuade the Mets to hold onto another player they would risk losing to waivers.

That player might be Short, a do-everything defender who was claimed this offseason from the Tigers. The 28-year-old played for parts of three seasons with Detroit, where he did not hit much but was solid defensively everywhere, seeing time at every position except left field, first base and catcher.

Short, who played shortstop Sunday and doubled — now 2-for-9 with a steal and walk this spring — wants to help wherever he can and might be a dark horse at third base.

“I’ve been kind of used to that my whole career, bouncing around. It’s a blessing and a curse: It’s a blessing where you can kind of put me anywhere in the field and then it’s a curse as in, better make sure you get all your work in at every position every day,” said Short, a Kingston native. “But I like it, especially competing for a job.”

Short, who added his offensive approach has changed as he tries to stay back a bit longer in the box, is out of options and on the 40-man roster, so he would need to pass through waivers if he does not crack the Opening Day roster.

Thompson is also out of minor league options but is not part of the 40-man roster, so he can be sent to the minors to start the season.

The brother of Klay Thompson has been an early star of camp, going 4-for-8 with a pair of home runs, and has had major league success (including an .860 OPS in 80 games in 2022).

But the 32-year-old struggled throughout last season with the Dodgers and White Sox, which brought him to free agency, which brought him to a minor league pact with the Mets.

He has been tweaking his swing and especially trying to prove he can hit lefty pitchers, as he has been much stronger against righties in his career.

“I don’t really think about [my opportunity with the Mets],” Thompson said. “I know that sounds cliche, but you really can only control what you can.”

There is a chance another hitter pounds his way into the Opening Day lineup. Because of their history — Choi as a longtime effective bat with the Rays, Voit as a home run threat who received MVP votes in 2020 with the Yankees — both sluggers are worth monitoring.

Through five spring games, Choi is 2-for-11 (with a home run and double) and Voit 1-for-15 with a walk.