New York Mets' Amed Rosario reacts after he was picked...

New York Mets' Amed Rosario reacts after he was picked off at second base after his double in the third inning of play against the Miami Marlins during their baseball game in Miami, Saturday, Aug. 11, 2018. (AP Photo/Joe Skipper) Credit: AP/Joe Skipper

MIAMI — Corey Oswalt has no guaranteed spot with the Mets beyond the next week or so, and as a rookie swingman, he has virtually no say in where he will end up when Steven Matz returns from the disabled list.

But via his lone method of influence — his work on the mound once every five games — he is making the Mets think awfully hard.

Oswalt turned in another quality start in the Mets’ 4-3, 11-inning loss to the Marlins on Saturday night, allowing three runs in six innings. In his past half-dozen major-league outings — spread out over three call-ups in a month and a half — Oswalt has a 3.94 ERA and 1.00 WHIP, numbers that would work for just about any team.

That’s why the Mets (48-66) are thinking about moving to a six-man rotation upon Matz’s return.

“As long as he keeps on being deserving,” manager Mickey Callaway said, “we have to consider it.”

Said Oswalt: “I don’t really think about that kind of stuff. I go out there and take it one pitch at a time and try to get as many outs [as possible].”

There are three primary considerations: Oswalt and a potential merit-based extended stay in the majors to try to prove himself; struggling Jason Vargas, whom the Mets want to have a chance to straighten himself out and build his innings total, and Jacob deGrom’s Cy Young Award candidacy, which rests in part on as many starts as possible.

If the Mets want, they can make all three work. Alternatives include sending Oswalt to the minors (or the bullpen) or getting a look at Vargas in relief, a role he hasn’t had since 2009.

Oswalt helped his case Saturday.

“He threw a really nice ballgame,” Callaway said of the righthander, who has walked three batters in his past four games (22 innings). “For him to have that kind of command at such a young age is rare. You don’t see it a ton. For him to go out there and attack hitters and get the ball where he wants to and not give free passes and be so efficient is a real plus.”

In the 11th, Jacob Rhame gave up a walk-off double to pinch hitter Bryan Holaday, Miami’s last available position player. That drove in Miguel Rojas, who led off with a single.

Oswalt cruised through his first three innings before finding trouble. He botched a potential inning-ending double play on Brian Anderson’s comebacker, opening the door for Martin Prado’s two-run single.

The Mets reached Miami righthander Dan Straily for three runs in 4 2⁄3 innings. All three came on Todd Frazier’s bases-loaded double in the fourth, moments after Brandon Nimmo walked on a slider that appeared to catch the inner portion of the plate (a decision by plate umpire Ed Hickox that paired nicely with Nimmo’s strike three off the plate in his previous at-bat).

The bullpen contributed four scoreless innings (two from Tyler Bashlor) before the 11th.

“They’re giving themselves a chance, throwing the ball over the plate,” Callaway said. “We have really good young arms — if they throw the ball over the plate, they’re going to do well.”

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