"He's having an MRI tonight and that's not a good sign," said Yankees manager Joe Girardi, who planned to discuss the quandary with general manager Brian Cashman. "He'll probably go on the DL. As far as the roster, I have no idea.

"Chances are we are going to need someone tomorrow."

The Yankees, losers of five straight, open a six-game road trip Friday night in Baltimore.

Molina doubled with one out in the fourth inning, then hurt himself a couple of steps before home plate when he scored on a double by Johnny Damon. He was replaced defensively following the fifth inning by Cervelli, who went 0 for 2 and is still looking for his first major league hit.

"He did it I guess two steps before home plate," Girardi said of the injury. "Go figure."

Molina, who was pressed into everyday duty last season when Posada was out with a shoulder injury, was hitting .273 with a homer and five RBIs.

Posada went on the DL after straining his right hamstring sliding during Monday night's loss to Boston. It was the same hamstring he hurt earlier in the season.

Cervelli is perhaps best known for breaking his wrist while blocking the plate against a hard slide by a Tampa Bay prospect during a spring training game in March 2008. The incident led to a benches-clearing brawl and the suspension of several players.

The Yankees are hopeful Cervelli will one day replace the aging Posada behind the plate, but they surely didn't expect it to happen so soon. The 23-year-old catcher, who appeared in three games for New York last September, was recalled from Trenton on Tuesday when Posada went on the DL.

Cervelli, who played for Italy in the World Baseball Classic, was hitting .190 with two homers and seven RBIs in 16 games with the Double-A club.