Manager Ron Roenicke said Weeks may be out two to six weeks after spraining his left ankle against the Cubs on Wednesday night.
Weeks beat out a throw in the second inning from Cubs shortstop Starlin Castro, but took a long stride, twisting the ankle awkwardly while touching the base. He stumbled to the ground.
"Some guys come back in two weeks and other guys, it's going to take six," Roenicke said. "Part of Rickie's game is speed on defense, speed on the base paths. Until he's right, it's going to be hard to put him out there because of the way he plays."
Weeks is hitting .272 with 19 homers and 43 RBIs in 104 games.
Infielder Eric Farris was recalled from Triple-A Nashville to take Weeks' place on the roster.