Brewers reliever Takashi Saito left Thursday's rehab assignment in Triple-A Nashville with a left oblique strain.
The 41-year-old right-hander is slated to return to Milwaukee on Friday to see Dr. William Raasch.
Saito, signed in December to a $1.75 million contract, made two appearances before being placed on the disabled list with a left hamstring strain earlier this season. Thursday was his first rehab appearance, and he was expected to be activated Saturday or Sunday in Houston if it went well.
Saito has a 2.24 ERA in six seasons (294 relief appearances) in the big leagues.
Alden Gonzalez and Adam McCalvy are reporters for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.