David Tennant's future in Hamlet is hanging in the balance but he said he hopes to return before the end of the theatre production's run.
Initially the Royal Shakespeare Company said the Doctor Who star would not return to play Hamlet before Christmas, but today a spokeswoman said the company did not know if he would return at all.
The actor is due to start filming next year's Doctor Who episodes just days later, and the show's writer Russell T Davies has already said he is hopeful he will be ready.
David said: "I am so grateful for all the terrific medical attention I have received and although it is frustrating to have to take it easy whilst all my friends and colleagues continue at the Novello Theatre every night, I am aware that I must listen to the experts and take my time.
"I am impatient to be back at work and sincerely hope to make it back some time before the end of the run.
"I am very sorry to disappoint anyone who booked to come and see me in Hamlet, but confident that you will be far from disappointed by Edward Bennett's performance in the title role."
A statement from the RSC said that David's doctors were "pleased" with his progress.
It said: "His recovery is encouraging so far, and we are not ruling out that he might be able to return to Hamlet during the last week of the run, although we cannot be more specific about the exact date of his possible return."