Saupold (groin) will start a rehab assignment Thursday with Triple-A Toledo, Jason Beck of MLB.com reports.
Saupold was given a 2-to-4 week timetable after landing on the disabled list at the start of the month, so he appears to be on track to hit the back end of that projection. The 26-year-old had been with the major league club when he got hurt, but he'd allowed eight earned runs and 13 hits in just 6.2 innings in the big leagues, so it remains to be seen if he'll rejoin the Tigers or stay with the Triple-A club when healthy.