DENVER -- Rockies manager Jim Tracy said first baseman Jason Giambi strained his left biceps during a ninth-inning at-bat on Sunday against the Giants and will likely be shut down for the rest of the season.
"I don't like his chances of seeing any more action during the course of the 2010 season," Tracy said. "It's definitely strained. ... He's sore today."
Tracy said Giambi will have an MRI exam to further evaluate the damage.
Giambi, who was 0-for-4 in Sunday's series finale against the Giants, struck out to end the game against San Francisco starter Matt Cain.
"He felt it," Tracy said. "I leaned over to my bench coach and said, 'He hurt himself.' You know how you could tell? Have you ever seen him take a swing and see the bat come completely loose out of his hands? He tweaked something there."
The 38-year-old veteran has been a key backup and clubhouse leader for the Rockies since he was acquired in August 2009. He's tied for the team lead with two walk-off homers (June 23 vs. the Red Sox and Sept. 12 vs. the D-backs), both in pinch-hit situations.
Giambi has started 35 games at first base and eight as a designated hitter, also earning a .393 on-base percentage as a pinch-hitter.