Injuries are really going to have an effect on the first leg of this tie. Andres Iniesta, Barcelona's extremely influential Spanish midfielder/forward, is out of today's match, and probably a doubt for the return leg next week. This is important because it is Iniesta who links play between the midfield and the strikers. Argentinians often wonder why Lionel Messi looks so much more impressive for Barcelona than he does when playing for his country, and I think the answer is he has Iniesta to get him the ball for his club.
Several other Barcelona players are either questionable or just returning from injury, including Xavi Hernandez and Gerard Pique.
Arsenal always seems to have an injury crisis, and today is no different. Andrey Arshavin and Samir Nasri, who tore Porto apart in Arsenal's last Champions League encounter, are both expected to be available despite slight injuries. Cesc Fabregas is very questionable though. He was injured against Birmingham at the weekend. I like Arsene Wenger, but just as with Robben and Bayern Munich, I have to ask why Fabregas was not rested at the weekend with such a critical match this week.
Arsenal's most important injury doubt may be William Gallas, who was expected to miss the quarterfinal entirely, but has surprised everyone by returning to training this week. He is in the squad tonight, but no one knows if he will feature in the match. Thomas Vermaelen will anchor the back line for Wenger, but without Gallas he doesn't really appear to have a worthy partner.
I predicted that Arsenal would win in London, and I am sticking with that prediction.