As if the Mets needed any further obstacles in their road to first place, starter John Maine left their 7-3 loss to the Marlins last night with an injury owing to this year's local cause du jour: toughing it out. Maine was in enough pain even before the game that his start was in doubt, and when Jerry Manuel visited the mound with assistant trainer Mike Herbst in the fifth inning, Maine persuaded them to leave him in. He surrendered a home run on the next pitch, was pulled one batter later, and still wasn’t pleased, as TV cameras caught him arguing with pitching coach Dan Warthen in the dugout afterward.

He’ll have an MRI today, and though the Mets can afford to be a pitcher short for a bit thanks to off days, Maine had apparently not learned much from this year’s spate of toughing-it-out injuries, which have been killing the Yankees all season.

Jorge Posada admitted in April that his shoulder had been bothering him for weeks, but kept playing anyway. He returned in July before he was 100 percent and had to go back on the DL, where he’ll stay until at least spring training 2009. Also in April, Phil Hughes felt discomfort in his rib cage, but kept it to himself (a move known as the Carl Pavano Special) and made his next start, despite wincing on the bench when he breathed. He hasn’t pitched since. Then there’s Alex Rodriguez, who, after missing a few days with a strained quad (coinciding with the birth of his daughter), returned to the lineup cautioning that he still felt pain and would have to take it easy. He didn’t heed his own advice, though, and played through it and went on the DL days later.

Maine said last night he expects to make his next start Sunday in Houston, but John Maine, M.D., might want to keep quiet so that John Maine, starting pitcher, can return in one piece. —Joe DeLessio

THIS ONE HURTS [NYP]