The injury is to Giles' right knee, the same knee that he had surgery on following the 2007 season. Giles injured the knee when he landed on first base during a game against the Seattle Mariners on June 18. The move is retroactive to June 19.
The Padres activated outfielder Scott Hairston from the 15-day disabled list to replace Giles. Hairston had been on the disabled list since June 3 with an injured left biceps.
Hairston is batting .327 with eight home runs and 23 RBIs for San Diego.