"He said he felt kind of a pop," Mets manager Willie Randolph said. "It doesn't look good."
"He said he heard a pop, and that is not a good thing. Usually, when something like that happens, you are put on the DL right away, but we'll just wait and see what the results are. It could have just been a combination of a real bad cramp or a strain. Any time a pitcher pulls a hamstring, that is usually automatic DL."
He retired Marlins catcher Matt Treanor on a groundout for the first out of the fourth inning, then immediately began grabbing his back and midsection, clearly in distress.
Martinez told 1050 ESPN New York's Andrew Marchand he feels "OK," and he thinks it is possible he could avoid the disabled list.
"I don't know if I'll have to go on the DL," Martinez said aboard Delta Flight 1790 from Miami to JFK.
He said it depends on what an MRI shows. Martinez landed at JFK a little after 3 p.m. ET and was expected to get his MRI later Wednesday. He was to be examined by Dr. David Altchek at the Hospital for Special Surgery.
Randolph said the team would make a quick decision if it needed to fill Martinez's roster spot.
"We weren't going to mess around," Randolph said.
Orlando Hernandez started the season on the disabled list.
"He's an unfortunate loss. Everyone knows what Pedro can do."
Martinez, entering the final season of a $53 million, four-year contract, went on the disabled list twice in 2006 with right hip inflammation and a strained right calf. That September, he was diagnosed with a torn rotator cuff, had surgery and didn't pitch in the majors for nearly 11 months.
But he went 3-1 in five starts late last season and was problem-free this spring -- giving the Mets hope that Johan Santana and Martinez would be powerful 1-2 atop their rotation.
Now, that's in question.
"We'll see how it plays out," Randolph said.
Randolph talked at length before the game about how he wasn't going to handle Martinez delicately this season, a much different approach than what New York used last year when the three-time Cy Young Award winner returned for the pennant chase.
That approach almost certainly won't last.
Martinez's best work Tuesday might have come at the plate. He worked a 12-pitch at-bat against Marlins starter Rick VandenHurk in the second, with the crowd getting louder every time the pitcher -- a career .094 hitter entering the night -- fouled one off to the backstop screen.
Martinez eventually struck out swinging to end the inning, but by then, VandenHurk had already thrown 55 pitches.
Jorge Sosa came in to relieve Martinez, who limped a bit as he walked off the field. Martinez -- who has battled foot, hip, calf and shoulder injuries over the past two seasons -- allowed home runs in each of the first two innings, the first time in his major league career that happened, according to the Elias Sports Bureau.
The Mets lost 5-4 as Robert Andino hit a walk-off home run in the 10th inning.
Information from The Associated Press was used in this report.