Posada (jammed shoulder) sits vs. Red Sox

NEW YORK -- New York Yankees catcher Jorge Posada was out of the starting lineup Saturday, a day after he was knocked over by Boston's Jason Varitek in a home-plate collision.

"He had a jammed shoulder last night," Yankees manager Joe Torre said. "He tried swinging the bat, got treatment this morning and it just didn't respond enough for him to be a player today. He
was able to do all the motions, but it just wasn't going to happen

Posada was not available for comment before Saturday's game but
said through Yankees spokesman Rick Cerrone that he could have been
in the lineup if the team needed him.

Torre, a former All-Star catcher, said he told Posada a story
from his playing days involving a catcher vs. catcher collision.

"When I was playing with the Cardinals, and Jerry Grote always
had a way of aggravating people, so you go and get him, and I got
him one time -- with my speed, I didn't get many people," Torre
said. "I thought I was going to get him again, and you close your
eyes just before you have that impact, and he was missing, I rolled
halfway to the dugout. I hit nobody."

Torre thought Varitek made a clean play on Posada, who was
trying to get a good grip on Derek Jeter's relay throw in the third

"If he had the ball, he could have sort of sidestepped him or
tagged him or put himself in better position," Torre said.

Gary Sheffield was out of the starting lineup for the third
straight game with a tight left thigh, which forced him from
Wednesday's game against Tampa Bay in the first inning. Sheffield
tried to take batting practice Friday but stopped when he couldn't
plant the leg. He planned to try to take BP again Saturday.

Torre said Sheffield would first return as a pinch hitter, then a designated hitter before going back to right field.

Right-hander Mike Mussina, recovering from elbow inflammation, planned to play catch for the second straight day. If all goes well, he intends to throw a bullpen session Tuesday and return to the rotation during the Yankees' final homestand, which runs from Sept. 19 to 25.