Arsenal boss Arsene Wenger has revealed that Kieran Gibbs has suffered a setback in his recovery from a hernia operation.
The 22-year-old full-back has been sidelined ever since being forced under the knife in November.
He has struggled to regain match fitness, forcing him to spend a longer than expected spell out of Wenger's plans.
It was hoped that he would come back into contention for Wednesday's trip to Aston Villa, but the Gunners have announced that he has been dealt another untimely blow.
"Kieran Gibbs has unfortunately had a setback and he is not back yet," Wenger told the club's official website.
"It's very disappointing because we had good hope that he would be back for tomorrow's game, but he is not available."
Arsenal have, however, received better news regarding the fitness of back-up goalkeeper Lukasz Fabianski and Japanese forward Ryo Miyaichi.
The pair have been nursing knee and ankle injuries respectively, but both are closing on a comeback.
"Ryo is joining in normal training on Friday, so he is completely back from injury," said Wenger.
"Fabianski has practised today (Tuesday) and should be available for next week."