Nasri in, Diaby out of Arsenal squad
The attack-minded Frenchman Nasri, in sparkling form this season, suffered the injury on January 30 and was expected to be out for three weeks.
However, he trained with the squad on Tuesday and Wenger, who said on Monday he would "not take a crazy gamble" on his compatriot, said Nasri had a chance of being involved in the last-16, first-leg match at Emirates Stadium.
"I will take no medical risk, he was quicker than expected - 17 days instead of 21 - and everyone is absolutely adamant that he is completely medically available," Wenger told a news conference at the London club's training base.
"It's down to me to make the decision." However, the news was not so good for midfielder Abou Diaby, who misses the match against the Spanish champions with a calf injury sustained playing for France last week.