By Nick Teale
William Gallas could miss the rest of the season, according to Arsène Wenger.
The defender had been out of action with a calf problem since the 1-0 win over Liverpool on February 10 but returned to the Gunners' starting XI against Barcelona on Wednesday.
However, he was forced off in the first half with a recurrence of the injury and Wenger accepts that it was a mistake to play him.
"Gallas is longer than three weeks," said Wenger. "I would say five weeks.
"It was a gamble which did not pay off and was a mistake, yes.
"He could be back maybe quicker but I just give myself five weeks because three weeks is a minimum and we will have to be a bit more cautious with him.
"So when we go to the Champions League Final, he still has a chance to play," he added with a smile.
When Gallas was forced off against Barcelona he was replaced by Denilson, with Alex Song dropping to centre back. Sol Campbell stayed on the bench and, at his pre-match press conference on Friday, Wenger explained why he did not opt to introduce the Englishman.
"Of course I could have done that," he admitted. "But at that stage we were struggling a bit everywhere, in midfield, at the back.
"It was very difficult. I think Song has all the attributes to play centre back and was a bit concerned about Sol's muscular problems."