Francisco Alvarez got his first start of the season in Sunday’s 7-2 loss to Miami and drove in the Mets’ first run of the game with a two-out single to the opposite field in the second inning, but also struck out with a pair of runners in scoring position with one out in the fourth and finished 1-for-4 on the day.

His defensive work was not as strong, as the Marlins went 5-for-5 on stolen base attempts.

“I’ll have to look at it,” Buck Showalter said of Miami’s success in running against Alvarez. “I’m not so sure they weren’t on the pitchers, most of them. Give him a chance and he’ll throw out the people he’s supposed to throw out.”

“I think I could have made better throws,’’ Alvarez said through an interpreter.

Showalter also pointed to some of the rule changes that make it harder to control the running game — besides the larger bases.

Want to catch a game? The Mets schedule with links to buy tickets can be found here.

“Probably one of the toughest jobs this year compared to last year is [controlling] the running game,” Showalter said. “They took away a really big weapon [by banning] the hold and step-off. That would stop guys from cheating in their break.”

Since pitchers have to work faster, it gives runners more of a chance to get a good jump.

Jazz Chisholm Jr. stole second and third in the top of the first, Nick Fortes swiped second in the fifth and Jean Segura took second in the eighth and moved to third on Alvarez’s throwing error.

But Alvarez didn’t become the Mets’ most prized prospect because of his defense.

It’s his bat that sets him apart.

Alvarez adjusted well with a 1-2 count in the second when he shortened his swing and went the other way.

“He’s got a chance to be an offensive contributor,” Showalter said before the game. “The priority — I think he understands it — is catching. He’s gonna impact the game the most there. Whatever we get somewhere else is nice, but not a prerequisite.”

The 21-year-old made his MLB debut last September and went 2-for-12 with a homer and four strikeouts in five games. He also struggled at the plate this spring before being sent to Triple-A Syracuse.

A calf injury to Omar Narvaez that will likely sideline the catcher for two months opened the door for Alvarez.

Showalter has indicated Alvarez will be used as a backup to Tomas Nido, but he hopes to have the rookie catch all the Mets’ pitchers in case he’s needed to play more later in the season.

Starling Marte left Sunday’s game with a neck strain after diving head first into Segura’s knee on a stolen base attempt in the bottom of the first.

He’s considered day-to-day, but Showalter indicated he’d continue to be monitored for any concussion symptoms.

Marte, who had doubled, swiped third with Francisco Lindor at the plate — but hit Segura’s knee and remained on the ground momentarily.

He was tended to by the training staff and briefly stayed in the game, stranded at third when Lindor and Pete Alonso struck out, but was replaced by Luis Guillorme to start the second, with Jeff McNeil moving from second base to right field.

“We’ll see what [Monday] brings, between the neck and the lump on his head,’’ Showalter said. “We didn’t want to take any chances. It looked like he tested pretty good as far as a concussion, but his neck had a pretty good whiplash.”

Showalter said there were issues with the pitch clock operators starting the clock “at the wrong time.”

“That certainly wasn’t our problem [in the loss], though,” the manager said.

Alonso entered having homered in three straight games. He didn’t go deep again versus Miami, but he did have an RBI single, giving him nine RBIs in his last four games.