Weeks had been out since spraining his left knee trying to turn a double play in Colorado on June 6. Corey Hart and Craig Counsell hit lead off in his absence, but Weeks returned to the top spot in the order against Baltimore. He finished the day 0-for-3.
"That's where he goes," manager Ned Yost said.
Weeks spent Friday and Saturday taking grounders and swings in the batting cage at Miller Park, convincing Yost that he did not need a minor league rehabilitation assignment.
In 59 games before going on the DL, Weeks hit .220 with seven homers and 43 runs scored.
To make room on the roster, the team optioned utility player Hernan Iribarren to Triple-A Nashville.