MIAMI - Steven Matz already has a sandwich named after him. Now the Mets might need him to be a hero.

Matz returns to the mound Sunday to face the Marlins in his first big-league outing since July 5. He has missed two months because of a partially torn lat muscle.

The Mets had hoped the Long Island lefty could help them go to a six-man rotation or even fill in for Matt Harvey or one of their other starters down the stretch to help preserve precious innings before the postseason.

Now the Mets are reeling from the news that Harvey was told by his doctor that he shouldn't throw more than 180 innings in his first season back from Tommy John surgery. Harvey on Saturday gave no indication he's going to ignore that advice, which could end his season after two more outings.

Twenty-four hours ago, Matz was returning as a luxury. Now his start takes on even more importance. If Harvey shuts himself down, Matz might become a necessity as the Mets try to hold off the Nationals in the NL East.

The good news is that the former Ward Melville star already has proved he can handle a big stage.

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Pitching in front of family and friends in his big-league debut on June 28, he had the kind of afternoon most kids can only dream about. Matz allowed two runs in 72/3 innings and had three hits and four RBIs against the Reds at Citi Field.

In his next outing, he threw six shutout innings at Dodger Stadium and drove in another run. Matz is 2-0 with a 1.32 ERA.

Asked if Matz can sustain that level of success, manager Terry Collins said: "Can he? Yes. Will he? I can't answer that. He went back down and obviously his last couple rehab outings were very, very good. So we're just hoping he's got 90, 92 pitches in him that are as good as we saw before. Again, we'll just have to wait and see."

Matz said he will be joined at Marlins Park on Sunday by Florida-based family members. There probably will be a few interested parties watching on Long Island, too.

The Mets were not a first-place team when Matz made his debut and had not added all the players they picked up before the trade deadline.

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"It's great," Matz said. "Got a lot of new faces in here. It's really cool. They're playing really well. The fans are really into it. So it's really exciting to just kind of step into it."

Before the Harvey news broke, Collins said of Matz: "It certainly makes it easier to give guys a start off when you've got somebody like that who can step in and be as good as anybody and not miss a beat. I mean, be really good. This guy's got a chance to be very special."

And at least he doesn't have an innings limit.