Maine left his start against the Marlins after 4 1/3 innings with a stiff right shoulder and could likely miss his next start, against the Astros. He will travel to New York on Tuesday morning for an MRI to determine the severity of his injury.
"You get soreness," Maine said, "but it's never felt like this before."
Which has given the Mets, who were handed a 7-3 loss by the Marlins, an entirely new reason for concern.
"If there's any, any, any pain, you will miss a start," manager Jerry Manuel told Maine following his outing. "You won't pitch your way through it."
The problem lies in the back of Maine's right shoulder -- not a trouble spot, according to pitching coach Dan Warthen -- and has caused him pain throughout recent weeks. But the Mets were not entirely concerned until they noticed a hitch in Maine's mechanics during a pitch sequence to Marlins catcher John Baker in the fifth inning on Monday.
Members of the Mets' training staff went out to check on Maine, returned to the dugout and then watched as Maine served up a home run to Baker one pitch later.
That didn't have much to do with the decision to remove Maine from the game, Manuel said, but what Warthen saw next did. Maine was compensating in other areas of his delivery to ease the pain in his shoulder, and Warthen was not willing to risk further injury.
"I was more worried that he was going to blow an elbow by trying to protect something else," Warthen said. "And that's what happens quite often. When you favor one area, another area has to take a lot more stress. We weren't willing to take that chance."
The Mets originally considered pushing this start back a day after Maine reported pain in the shoulder last week but opted not to under the assumption that an extra day wouldn't do much good. And any paranoia may have seemed misguided after Maine breezed through his first four innings, striking out five batters and walking one.
Even after he removed Maine from the game, Warthen was not entirely concerned with his pitcher's health. The injury has nothing to do with the dead arm that affected Maine earlier this month in St. Louis, nor is it the type of injury that should cost him significant time. He could miss one start, but with two off-days over the next week, there are easy ways to skip his spot while keeping him in the regular rotation.
That's not Maine's ideal scenario, of course, but he understands it. And everyone will understand much more after the MRI on Tuesday afternoon.
"I'm frustrated, because I want to go out there and pitch," Maine said. "But I understand where they're coming from. What's a couple more innings? For me to just go out there and pitch a couple more innings is really not that big of a deal."
Anthony DiComo is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.