Roma coach Luciano Spalletti admits captain Francesco Totti's hamstring complaint is causing him concern.
Totti was passed fit to travel to England for the second leg of their UEFA Champions League encounter with Manchester United, having missed Saturday's win over Catania.
The forward is the heartbeat of the Roma side and will be given every opportunity to prove his fitness, but Spalletti admits it is a worry ahead of Tuesday's encounter.
"It is the thing I am most concerned about at the moment," he said.
"I need to see him in training and check on him tomorrow. Hopefully he will be able to play because we need him."
Roma are protecting a 2-1 lead from the first leg, but will be without the suspended Simone Perrotta, although David Pizarro is available following a ban.