Between starts, Steven Matz is throwing his bullpen sessions like normal, though he is cutting down on how many pitches he throws. He is still taking medication to quell inflammation in his elbow.

For now, despite a large bone spur that has tested his tolerance for pain, the Mets lefthander remains committed to holding off on surgery.

Yet even after an encouraging performance in Tuesday night’s 5-2 loss to the Marlins, the Mets intend to weigh Matz’s fate on a start-by-start basis. Indeed, it’s not a matter of it the lefty needs surgery, but when.

“With the way I felt out there tonight and I was able to command, I feel like this right where I need to be,” said Matz, who hopes he has found a way to manage his condition.

Matz allowed two runs in seven innings, his longest start since his last victory on May 25. It wasn’t enough.

Giancarlo Stanton, the Marlins’ $325-million masher, has spent much of the season inspiring questions about his pedestrian production. But he homered twice, knocked in all five of this team’s runs, and squashed a seventh-inning rally by making a sliding catch.

advertisement | advertise on newsday

With that, the Marlins ended the Mets’ winning streak at five games and spoiled Jose Reyes’ first game back with the franchise that made him into a star. Leading off and starting at third base, Reyes finished 0-for-4 in his first big-league game since the Oct. 31 domestic-violence arrest that effectively ended his tenure with the Rockies. It landed him a 52-game suspension, and paved his path for a controversial homecoming.

Yoenis Cespedes blasted a solo shot — his 21st homer of the season — and reached base three times. His outburst came on the same day he was named an NL All-Star, along with Jeurys Familia and Noah Syndergaard.

Alejandro De Aza blasted a pinch-hit homer in the eighth to cut the deficit to three, though it wasn’t enough. Nor was Matz’s best start since revealing that he’s fighting through a bone spur.

“I don’t think he’s feeling anything right now,” manager Terry Collins said. “From our experience, it will flare up and then there’s days it doesn’t bother him at all. We’ve had the same answers from Noah.”

Of course, what Syndergaard is enduring something different. His bone spur may not require surgery. For Matz, it’s a given.

Mets videos

On Tuesday, he worked quickly and cruised, striking out six while walking just one. But his biggest mistake came back to bite him. Stanton lashed a two-run in the seventh inning. The low liner marred what was perhaps Matz’s best outing.

Stanton wasn’t done. He blew open the game in the eighth. With the Mets trailing just 2-1, reliever Erik Goeddel paid the price for falling behind in the count. He grooved a 3-and-1 fastball over the plate, leaving it for Stanton to bash a three-run homer into the upper deck in leftfield.

“He’s a great hitter, he’s got great power, he’s not hitting very good,” said Collins, using Stanton’s .218 average coming into play as justification for not intentionally walking him when he got to three balls. “So you’ve got to make a pitch. We didn’t make a pitch.”

For the first time all season, Stanton logged a multi-homer game, leaving the Mets (45-38) needing a victory in Wednesday rubber game to collect another series win.

The Mets had outscored their opponents 40-17 in their five gams. But they couldn’t touch Marlins lefty Wei-Yin Chen, who entered play with a 5.11 ERA.

advertisement | advertise on newsday

Chen gave up Cespedes’ solo blast but nothing else in seven innings, wasting a strong effort by Matz, who intends to stay in the rotation.

“This is something I’ve been dealing with,” he said. “So I know what to expect.”