John Maine pitching early in the game at Citi Field...

John Maine pitching early in the game at Citi Field against the Marlins. (April 7, 2010) Credit: David Pokress

One of the pillars of the planned success of the 2010 Mets is a return to pre-shoulder surgery form by John Maine.

Maine was bumped up to the No. 2 spot in the Mets’ rotation at the end of spring training in a move manager Jerry Manuel said was mostly about his history against the Marlins, last night’s opponent at Citi Field. It was also a chance for Maine to grab the role of “starting pitcher other than Johan Santana whom the Mets have confidence in.” That spot is still up for grabs, with Jonathon Niese the next contestant, then Mike Pelfrey, then Oliver Perez . . .

Maine did not have the look of a No. 2 starter last night. His fastball — once a rising 95-mile-per-hour blur — barely topped 90, and the fastball-loving Marlins took advantage.

Maine allowed four runs in five innings. He gave up eight hits, walked three and struck out three. Of his 92 pitches, 53 were strikes.

Manuel admitted before the game that the Mets’ rotation has him “somewhat concerned.” He was hopeful he would see the old Maine last night, even though the righthander had a 7.88 spring training ERA. The Mets believe he is fully recovered from the shoulder weakness that limited him to 15 starts last season after surgery late in 2008.

“If he’s good , he is a guy we feel can get us late into a ballgame,” Manuel said. “The thing about John Maine is he’s always won. Somehow despite even the struggles he had physically last year, he was still able to win some games for us. Hopefully now that he’s healthy and strong, we’ll get some good results.”

The good feelings the Mets had from Monday’s Santana-fueled Opening Day win lasted about three batters into last night’s game. Cameron Maybin doubled with one out in the first and Hanley Ramirez lashed a single down the third-base line for a 1-0 Marlins lead.

The Mets tied it in the bottom of the first on Alex Cora’s leadoff triple and Luis Castillo’s sacrifice fly. Jorge Cantu homered in the third to give the Marlins a 2-1 lead. Maine, his command deserting him, then walked Dan Uggla and bounced a wild pitch before John Baker singled to center to make it 3-1.

Ramirez led off the fifth by hammering the first pitch off the roof of the Mets bullpen in right-center for a 4-1 Florida advantage. Maine did have good numbers against the Marlins coming in (5-2, 3.12 ERA). And he had won six straight at Citi Field and had a home ERA of 1.98 in the ballpark’s first year of existence.

Mejia allows run in debut. Jenrry Mejia made his major-league debut in the sixth with the Mets trailing 4-1 and showed the electric fastball that earned him a bullpen spot at the tender age of 20.

But the Marlins turned around three of those fastballs, including a 97-mile-per-hour one that Cody Ross sent into rightfield for a single. That was Mejia’s second pitch as a major-leaguer. He first was a 95-mph strike. Mejia also gave up a long double to Gaby Sanchez and, after a strikeout of pitcher Ricky Nolasco, surrendered an RBI single to Chris Coghlan. That was the only run Mejia allowed as Maybin and Ramirez both grounded out.

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