Oakland Athletics slugger Jason Giambi has been placed on the disabled list with a strained right quadriceps muscle.
Giambi, 38, suffered the injury playing first base in Sunday's 1-0, 10-inning loss to the Los Angeles Angels.
He was replaced by Bobby Crosby in the top of the ninth inning.
"I'm not aware of a specific play," Athletics manager Bob Geren said. "[But] he has given me his all.
"It is just something we're going to try to get Jason healthy. It is something that has been coming on."
Giambi is struggling mightily this season, hitting a paltry .193 with 11 home runs, 40 runs batted in and 39 runs scored in 83 games.
He has just seven hits in his last 57 at-bats.
"Sometimes that [a break] can be beneficial if you want to look at a positive," Geren said.
Giambi broke into the major leagues in 1995 with Oakland, and won American League most valuable players honours in 2000.
One year later, he signed with the New York Yankees for seven years and $120 million US contract, but became a free agent when they declined a $22-million US contract option for this season.
Giambi rejoined Oakland for a reported $4 million US on Jan. 7.
He is a lifetime .282 hitter with 407 HRs, 1,319 RBIs and 1,155 runs in 1,933 MLB games.