New York Mets starting pitcher Zack Wheeler works against the...

New York Mets starting pitcher Zack Wheeler works against the New York Yankees in the first inning of a spring training baseball game Wednesday, March 7, 2018, in Port St. Lucie, Fla. Credit: AP / John Bazemore

PORT ST. LUCIE, Fla. — As spring training hit the halfway point this week, the competition among Steven Matz, Zack Wheeler, Robert Gsellman and Seth Lugo for a spot in the back of the Mets’ rotation is still very much a competition.

“We have a battle going,” manager Mickey Callaway said.

Wheeler on Wednesday made his strongest case yet, tossing three scoreless innings (49 pitches) and striking out four in an 11-4 loss to second-string Yankees. He scattered four hits — all singles — and didn’t walk anybody.

After pitching his first game in a week, Wheeler said he felt more comfortable than he did last time, when he allowed a run on three hits in one inning of relief.

“[He has been] getting more repetitions and stuff like that, so everything is starting to feel a little bit better and natural,” Wheeler said.

Wheeler’s performance stands in stark contrast to Matz’s recent efforts. The lefty has allowed 10 runs in 1 2⁄3 innings across two games.

Righthanders Lugo (3 1⁄3 innings, one run Tuesday) and Gsellman (3 2⁄3 innings, one unearned run Wednesday) have been getting enough work in relief that the Mets could pick them for the rotation. Callaway also mentioned righthander Rafael Montero while discussing the No. 5 starter spot, though Montero got roughed up for five runs (two earned) in one-third of an inning against the Yankees.

“I really couldn’t tell what his intent was with his pitches,” Callaway said of Montero.

Wheeler, Matz, Lugo and Gsellman can all be optioned to the minors. Montero cannot.

With Matt Harvey having a spring that would qualify as both uneventful and impressive, there would seem to be — pending unforeseen injuries — just one starting gig for the group.

The Mets could choose one or more of the non-chosen starters to open the season in the bullpen, likely as multi-inning options.

“We’re thinking about it,” Callaway said. “We’re kind of going back and forth about what we think every day. All the coaches sitting around, we’ll talk about those types of things. They’re making it tough on us right now. They’re pitching really well.”

That was particularly true for Wheeler Wednesday. With an extended stretch between outings, Wheeler threw two bullpen sessions instead of one, focusing with pitching coach Dave Eiland on his curveball and two-seam fastball.

The curve was working Wednesday, as it was for much of last season, when opposing batters hit .214 against it (Wheeler’s most effective pitch by that measure).

“It opens up a wide range of options for you,” Wheeler said. “You can go back to back, which a lot guys won’t swing at a big curveball like that. If they do, more than likely they aren’t going to square it up. That opens up a lot of different options. Keep guys on their toes, and whenever you can flick that in there, it helps the pitcher out a lot more and makes it a lot easier for us.”

Said Callaway: “Get a guy like that with really good stuff and they have to worry about multiple pitches and they can’t start eliminating pitches, then you can become very effective.”

Wheeler, for his part, is trying not to think about the Mets’ looming personnel decisions.

“I can’t help what everybody else is doing,” Wheeler said. “I just worry about myself and go out there and try to give myself the best chance to succeed. Whatever happens, happens. I’m just here to pitch and be healthy and give the team innings.”

A couple more outings that look like Wednesday will help.

“Everybody else is throwing good, too,” Callaway said. “To make that decision is going to be very tough for us toward the end.”