Molina has been a star understudy while New York has coped with the defensive absence of Jorge Posada, who is recovering from a right shoulder strain that will not permit him to throw with the necessary velocity to catch baserunners.
The 32-year-old Molina had another two hits in Sunday's 8-5 loss to the Red Sox, raising his average to .364, but finally had to come out of the game in the eighth inning for pinch-runner Wilson Betemit as the Yankees were threatening.
"I stayed as long as I could," Molina said. "It just feels tight. With these things, you can't play around. You have to be 100 percent."
"It was pretty bad," Yankees manager Joe Girardi said. "Basically what he did is he sucked it up for us."
The Yankees will make a roster move to bring in another catcher for Monday's game at Tampa Bay -- likely Triple-A backstop Chad Moeller -- but have not yet decided if Molina will need to go on the 15-day disabled list.
Posada was instructed not to throw and the Red Sox stole twice on him; he will try throwing again on Monday at Tropicana Field but said that he cannot catch.
"We're going to have to make some kind of move to get a catcher in here who can actually play," Girardi said.
Bryan Hoch is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.