It's hard to tell exactly what's going on with Maine. He'll visit a doctor Monday for more tests that should determine what the next move is for the oft-injured pitcher.
"There's still something going on back there," said Maine, who had surgery in September 2008 to remove a lesion from the back of his right shoulder socket. "Who knows what it is? It's something that has to be found. If it comes back good, you know I'll deal with it and pitch, like I have been."
Maine has struggled all season, going 1-3 with a 6.13 ERA in nine starts. He was placed on the 15-day disabled list Friday with right shoulder weakness after he missed three months last year with a tired shoulder, which he blamed on overwork following the operation.
"I've never had anything before in my life," Maine said. "The last two years, I don't know, I just want to go out and pitch. That's the only thing. ... It's upsetting."
Maine was lifted after just five pitches Thursday night in Washington because manager Jerry Manuel and pitching coach Dan Warthen were concerned about his lack of velocity. The 29-year-old right-hander disagreed with the decision and let Manuel know during a spirited discussion in the dugout.
Maine had been saying he felt the same as he had all season, but appeared to be backing off a bit before the Mets beat the New York Yankees 5-3 on Saturday night.
"It's the same area," as his shoulder discomfort last year, Maine said. "But I don't exactly know what's going on. That's why we're going to go see a doctor."
The Mets are off Monday, giving Manuel some flexibility as he lines up his rotation for a three-game series against NL East-leading Philadelphia. Raul Valdes or knuckleballer R.A. Dickey will start in Maine's spot Tuesday night, followed by Hisanori Takahashi and Mike Pelfrey.
Manuel indicated he was leaning toward Valdes for the opener. The lefty pitched five innings after Maine departed Thursday night.
While Maine's status was largely unclear, reliever Ryota Igarashi rejoined the team after making four minor league rehab appearances to test his injured left hamstring. Manuel said he would be activated Sunday.
Second baseman Luis Castillo returned to the lineup against the Yankees after being limited to pinch-running duties in the Mets' 2-1 loss on Friday night. He went 0 for 3 with a walk.
Castillo has been hampered by a bruised left heel and admitted he isn't 100 percent.
"It's going to be a day-by-day thing," Manuel said before the game. "He has an injury where it's kind of strange. It's almost like he's playing with a little rock in his shoe. You can play with it, but it's going to be some discomfort."