The France playmaker has been the Gunners' form player this season, playing the best football of his four seasons in England.
Nasri suffered a hamstring injury in the FA Cup fifth round match against Huddersfield and has been on the sidelines for the last two weeks.
It was thought he was at least another week away from fitness but Wenger revealed he was surprisingly in contention for the home leg against Barca, although the Arsenal boss will not take any risks with the player's fitness.
"I would say he has a chance," said Wenger.
"He has tests, one tomorrow and one on Tuesday. I will not take a crazy gamble but physically he has worked very hard; physically he is ready. It is just if there is a risk of a setback or not."
Asked if the 23-year-old was eager to face the La Liga giants, Wenger added: "Who isn't? But we have the Carling Cup final too... we have so many big games it is important not to be stupid as well."