Giles was kept out of the lineup in the Padres' last game and did not start again for the first game of the Padres' three-game series against the Marlins on Monday.
Giles continues to be available to pinch-hit but will take a couple of days off before playing in a full game.
"His hamstring wasn't improving because he was playing," Padres manager Bud Black said.
Black said that they are going to back off from Giles starting games to allow the hamstring more time to fully heal. Giles doesn't feel any pain when he's hitting.
It is certain that Giles will not be back in the starting lineup for Tuesday's game, but a timetable after that has not be determined.
Also, Padres catcher Josh Bard took batting practice and ran the bases on Monday prior to the game. Bard will be behind the plate for practice on Tuesday. Black says that Bard will be in a uniform in either Triple-A Portland or Class A Elsinore in the next five to 10 days.
Bard has been out since May 21 when he sprained his ankle after the St. Louis Cardinals' Albert Pujols slid into his foot during a play at the plate.
Ronald P. Clark is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.