Santana (illness) joined Triple-A Worcester on Wednesday to begin a rehab assignment, Bill Koch of The Providence Journal reports.
Santana has been on the COVID-19 injured list since Sept. 11 after testing positive for the virus, so he could need at least a few days' worth of workouts before the Red Sox are comfortable activating him. If Santana rejoins Boston for its final series of the regular season this weekend in Washington, he would likely serve as a utility man.