Chelsea manager Andre Villas-Boas admits Didier Drogba might miss Sunday's clash against Manchester United as the Ivory Coast striker continues to recover from concussion.
Drogba was concussed in a collision with Norwich goalkeeper John Ruddy during Chelsea's 3-1 victory on August 27 and has yet to return to action.
The 33-year-old resumed full training with Chelsea's first team squad on Friday, but Villas-Boas believes the trip to Old Trafford had come a week too soon for Drogba.
That leaves Villas-Boas to select Fernando Torres, Nicolas Anelka or Daniel Sturridge as the central figure in his attack against the in-form champions.
"Didier had a medium intensity session yesterday (Thursday) and a high intensity session today (Friday) but it is a week too soon to go with him for Man United," Villas-Boas said.
Villas-Boas also has a concern over the substitute goalkeeping position as both Ross Turnbull and Hilario - who are competing to deputise for first-choice Petr Cech - have been struggling with injuries.
Hilario suffered a hip injury this week and Turnbull is working his way back to fitness after several weeks on the sidelines, but Villas-Boas expects at least one of them to recover in time for the United game.
"Hilario took a big knock to his hip. He went for a scan and we are trying to discover the extent of injury. Turnbull is 80 percent fit after recovering from injury in a reserve game. One of them will be on the bench," Villas-Boas added.