Arsenal will be without Kieran Gibbs for up to six weeks and not three as was original thought.
Gibbs went down with just over half an hour into Arsenal's 2-2 draw with Liverpool on Wednesday night and, despite being able to return to the pitch after treatment, he was forced off with 37 minutes on the clock.
At the time it was thought that the thigh injury would keep him sidelined for three weeks, but it is worse than feared with Arsene Wenger admitting he is unlikely to have the defender available until March.
The extended recovery time could result in Gibbs missing both Champions League last-16 ties against Bayern Munich.
"It will be four to six weeks (out)," Wenger told reporters on Friday. "I believe Gibbs will be out for the Champions League."
Wenger dipped into the transfer market late by signing Nacho Monreal from Malaga but the left-back will not be available for the Champions League because he has already played in the competition this year.
With both Gibbs and Monreal ruled out, Wenger has confirmed Andre Santos will have to take over at full-back, something which might not sit too well with Arsenal fans.
"I cannot play Monreal. Santos could have a key role," Wenger revealed.