Who's going to be starting pitcher for Mets on Monday?

There were two concerns for Buck Showalter before the Mets’ 6-2 loss to Miami at Citi Field on Sunday, and both revolved around Monday.

One was a labor issue.

“Right now, on my mind immediately: Is [David] Peterson’s wife going to go into labor before he starts tomorrow?” the manager said. “We’re preparing for that.”

No. 2: “We know we’ve got to go to 13 pitchers,” Showalter said of MLB’s decree for Monday’s cut from 14. “We know we have to make some moves.”

Righthander Trevor Williams could be a candidate to fill in for Peterson in the series finale if the lefty needs to go on the paternity list. Williams has appeared in 12 games, five of them starts. He’s 1-2 with a 4.50 ERA in a starting role as opposed to 0-1 with a 2.30 ERA in a relief role.

If the paternity list comes into play, that would buy up to three days before the decision would have to be made on which pitcher will need to go.

Hunter returns

Tommy Hunter went through a lot last year. His Mets season basically was finished in May. There were six herniated discs in his lower back, causing intense pain.

“I had four epidurals, nerve blocks, nerve ablasions and the one laminectomy-discectomy that showed it all,” Hunter said.

But it wasn’t the end for the 35-year-old righty. The Mets traded him to Tampa Bay last July while he was on the injured list, and he re-signed with them in April and went to Triple-A. He was called up on Friday from Syracuse and made his major-league season debut on Sunday.

Hunter worked 1 2⁄3 innings in relief and was charged with an unearned run. He allowed no hits and no walks and struck out two. “It felt good to be back,” he said. “It’s obviously why we play. It was a long, long, long wait . . . It’s nice to be back.

“I feel good. I’m healthy, finally.”

One motivation to return was a photo.

Hunter wanted to be on a big-league field and have one taken with the youngest of his three sons, his 1-year-old. His wife, Ellen, had mentioned pursuing a comeback and taking the photo after he didn’t have pain throwing.

“We got one the other day,” Hunter said. “It was pretty cool. Check that off the book and now let’s play. It was just fun. Smiles, that’s what my wife really wanted. Thanks to her, that’s why I’m standing here.”

Extra bases

The Marlins’ Jerar Encarnacion became the first player since at least 1901 to have a grand slam and an outfield assist in his major-league debut . . . Jeff McNeil has a .455/.556/.682 slash line in his seven-game hitting streak . . . James McCann (wrist) caught and went 2-for-4 with a walk in his third rehab game with Double-A Binghamton. Showalter declined to say how long the rehab assignment will last.