PORT ST. LUCIE, Fla. — Before coming to the Mets in a midseason trade in 2015, Addison Reed struggled so badly that he found himself in the minor leagues. But since then, he has been one of the best relievers in the National League.

The timing of that ascent may prove beneficial as the Mets approach a new season.

After an offseason arrest for domestic violence, closer Jeurys Familia will almost certainly be suspended to begin the season. Reed will be expected to fill the breach, giving the Mets an experienced presence at the end of games.

“Ever since I’ve come over here, everything’s kind of clicked,” he said on Thursday.

Reed, 28, is no stranger to closing games. From 2012 to 2014, he recorded 101 saves for the White Sox and Diamondbacks, though his ERA during that span was 4.22.

But in 2015, Reed stumbled out of the gate. By May, he had been bumped as the Diamondbacks’ closer. By June, he was demoted to Triple-A Reno, where he spent a month trying to make mechanical changes to regain his form.

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Reed pitched to a 1.65 ERA in his return to the Diamondbacks. Nevertheless, Reed was traded to the Mets in late August in a waiver deal for two minor-league pitchers. It may be one of the best trades during the tenure of general manager Sandy Alderson.

With the Mets, Reed ironed out his delivery, which translated to sharper command of his fastball. The results have been transformative.

In 80 appearances in 2016, Reed finished with a 1.97 ERA in 77 2⁄3 innings. While Familia recorded an NL-high 51 saves, Reed proved equally valuable in the setup role.

Reed even seems open to the idea of expanding that role. He watched the postseason, when the Indians’ Andrew Miller was deployed to great effect in various midgame situations, breaking the traditional mold of bullpen usage. Reed believes it could mark the start of a trend, and it’s a concept he’d be willing to try.

Said Reed: “I definitely think it’s going to change how [managers] start using relievers.”

But for now, with Familia likely facing a suspension, Reed’s immediate responsibilities will take on a more traditional form.

“It’s a good thing that I’ve closed in the past,” Reed said. “Whether I’m closing at all this year or throwing the eighth or the seventh inning, it doesn’t matter to me. Having closing experience will definitely help.”

Notes & quotes: Lefty relief specialist Jerry Blevins officially agreed to a reunion with the Mets, signing a $5.5-million contract that includes a $7-million team option for 2018. Blevins could increase his salary by $100,000 in each season per incentives. The deal also includes a $1-million buyout, giving him a guaranteed $6.5 million. To make room on the 40-man roster, utility man Ty Kelly was designated for assignment.