Reed sustained the injury, which he described as both a bruise and a muscular injury, during last Sunday's regular-season finale against the Cincinnati Bengals.
"I'm just trying to get myself together right now," Reed said Wednesday. "I'm trying not to let it stop me. It's painful. I'm just dealing with it. I'm going to rehab up until this Sunday and another good reason not to be playing Indy because we would have been playing Saturday. That's the only thing honestly I was praying for."
Reed missed the season's first six games after undergoing offseason hip surgery.
"They seem good," Harbaugh said, according to the Ravens' official website. "They were out here. Seem like they're moving around OK. I'm always optimistic."
Oher, wide receiver Derrick Mason (abs/ankle) and kick returner David Reed (wrist) were full participants in Wednesday's practice.