Massimiliano Allegri said he was lucky to have such a big squad as Thiago Silva became the latest player to break down with injury, virtually ruling him out of Wednesday\'s UEFA Champions League clash with Barcelona. The Brazilian lasted only ten minutes of yesterday\'s 2-1 win at Roma before hobbling off with a muscle problem in his leg. Allegri said afterwards it would be almost impossible for his centre-back to be fit to face the European Champions at the San Siro. Daniele Bonera switched from full-back into the centre and formed a solid partnership with Philippe Mexes, earning praise from Allegri. \"I think it will be impossible for him (Silva) to play on Wednesday, he has a problem in his flexor muscle,\" said Allegri. \"Fortunately we have a big squad of 33 players, some of whom have found consistency by playing more regularly. Bonera is doing very well, both in the centre and at full-back. \"I wanted to take the risk (with Silva) because it was a vital match, the league is as important as the Champions League and as I don\'t have many full-backs I wanted to rest (Gianluca) Zambrotta (who replaced Silva). In the morning, after the last treatment, Thiago Silva showed no signs of problems, but that\'s how it went.\" Allegri was already missing the likes of forwards Robinho, Pato, Antonio Cassano and Maxi Lopez as well as full-backs Ignazio Abate and Luca Antonini and defensive midfielder Mark van Bommel. Kevin-Prince Boateng was only fit enough for the bench on his injury comeback. It has left Allegri scratching his head to find a reason for why so many of his players are out injured. \"It\'s not good that with a month to go in the season we have so many injuries, now is the time that you make a difference,\" he moaned. At least top scorer Zlatan Ibrahimovic overcame a back problem to play, and star in the victory over Roma. The big Swede scored both goals, taking his tally to 22 in 23 league games in this campaign. \"My back\'s been hurting for a few days but I have too much adrenaline on the pitch to think about it,\" said Ibrahimovic. \"I feel good physically and mentally and I\'ve played almost all the games, except those where I was suspended. That\'s important because normally at the end of the season you feel tired but instead I\'m in good shape.\" Looking forward to the clash aainst his former employers, Ibrahimovic insisted there was no disadvantage to being drawn against the dazzling Catalans. \"If you want to win the Champions League you have to play these games,\" he said. \"They\'re the best team in the world and the favourites for the Cup but we don\'t have anything to lose and they have a lot (to lose).\"