ST. LOUIS -- San Francisco Giants pitcher Matt Cain was placed on the 15-day disabled list Friday with a strained right hamstring, one day ahead of his scheduled start against the St. Louis Cardinals.
The move was made retroactive to May 22, and outfielder Juan Perez was recalled from Triple-A Fresno.
"We're going to take the safe route," Giants manager Bruce Bochy said. "He wanted to pitch, but at the same time he's feeling a little something.
"It's just not worth the risk."
Bochy said if it was mid-September and the Giants were in a tight race, Cain would have pitched.
Cain is 1-3 with a 3.66 ERA in eight starts. Petit is 3-2 with a 5.08 ERA in 14 games, four of them starts.
San Francisco catcher Buster Posey missed his second straight start with tightness in his lower back.
"He's doing better," Bochy said. "Give him another day."
Hector Sanchez, in a 2-for-23 slump, started again in Posey's place.
Perez was 1 for 20 in an earlier stint with the Giants. He was batting .333 with eight RBIs in 20 games at Fresno.