PORT ST. LUCIE, Fla. — As the rest of the Mets’ outfielders tracked down fly balls, Jay Bruce stood on a neighboring practice field, where he navigated new territory.

Terry Collins stood nearby, not far from the first-base bag. The manager typically leaves the hands-on instruction to other coaches. But in this case, Collins watched Bruce take a few grounders, then talked him through various scenarios he might face at first base.

Then the drill began. And there was Bruce, with Collins still standing guard, charging at bunts and making throws to the bases, a career outfielder in the first stages of a transition that could reshuffle the Mets.

“I’m obviously nowhere near close to being comfortable to play over there,” Bruce said, though it’s clear that his new endeavor suddenly has become a higher priority for the Mets.

The Mets already have a first baseman, and if he’s healthy, Lucas Duda is a worthy power threat in the lineup. But after missing much of last season with a stress fracture in his back, Duda again is banged up, leaving the Mets to look for safeguards.

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Enter Bruce, whose potential move from rightfield to first base could lessen the outfield logjam and clear a spot on the team for Michael Conforto, the former first-round draft pick who homered on Sunday to extend what has been a scorching start to spring training.

The Mets still hope that Duda’s latest brush with the trainer’s room doesn’t linger. He has soreness in his hips that he believes might be related to compensating to relieve pressure in his back. The symptoms became bad enough for him to undergo cortisone injections over the weekend that will keep him from baseball activities for a few more days.

“It’s just a spasm in my back, I guess, so we’ll take a few days right now instead of taking two weeks down the road and just being cautious,” said Duda, who believes that the new back malady isn’t related to the stress fracture that limited him to 47 games a year ago.

But Duda’s injury history and the need for protection at first base have spurred the Mets into action. Last season, with Duda out for a significant portion of the season, Mets first basemen posted a .718 OPS that ranked second to last in the National League.

Collins was noncommittal about when Bruce might play first base in a game, but he will continue doing work at first base, as he did on Sunday.

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“I don’t plan on having to do it because I hope that Lucas is healthy and he gets through whatever is going on,” Bruce said. “But I am going to work at it and I want to give myself a chance and give the team a chance. I’m not going to go over there and be a butcher.”

Bruce hasn’t played the position regularly since his freshman year of high school. His big league resume at first base consists of three emergency starts in 2014 while with the Reds.

But in a controlled environment, Bruce looked comfortable fielding grounders and moving into position in various situations. On one bunt, he charged, made a clean pickup and fired a strike to third base.

“I liked everything I saw today,” Collins said. “It looks like he’s got certainly the athleticism, he’s got the hands, he’s got the arm angle, he made some throws in our drills that you wouldn’t be able to expect an outfielder to be able to make. Yet he does. If that’s where we have to go, I think we’ll be fine.”