Horn on Saturday was activated to the 53-man roster, the team announced. He was limited in Friday's practice, so it remains unclear as to whether the 2021 first-round pick out of South Carolina will be used.
But Horn has a chance to get back on the field after suffering a hamstring injury that required surgery after a Week 1 loss at Atlanta. The Panthers had until Monday to activate him before his 21-day window to return from injured reserve expired.
"He's had a good week," interim coach Chris Tabor said.
The secondary already should be strengthened by the return of cornerback CJ Henderson, who cleared the concussion protocol and was a full participant in Friday's practice.
There's also a chance the Panthers (1-10) get outside linebackers Yetur Gross-Matos (hamstring) and Marquis Haynes (back) back to face Buccaneers quarterback Baker Mayfield, who began last season as the starter for Carolina. Both linebackers were listed as questionable Friday.
The Panthers will be playing their first game since coach Frank Reich was fired Monday. Tabor, the special teams coordinator, was elevated to interim head coach.