Sullivan (back) was a limited participant in the Panthers' practice Thursday, Darin Gantt of the Panthers' official site reports.
Sullivan returned to practice in a limited fashion Wednesday after being held out of practice last Thursday and Friday with a back injury. While the exact nature and severity of this issue are still unclear, it proved significant enough to keep him sidelined for Carolina's Week 5 loss to San Francisco. Sullivan recorded the first reception of his NFL career in Week 2, but he's played just six offensive snaps over three games so far this season.