Valdes is suffering a strain of the capsular ligament in his left knee.
Barcelona coach Pep Guardiola says his die have proved their worth after winning 2-1 against Bilbao thanks to gaols from David Villa and Messi.
Guardiola has dismissed speculation linking the club with a move for Arsenal midfielder Jack Wilshere, saying that Wegner will not want to sell his best players (*COUGH* Fabregas *COUGH*)
Valdes is likely to miss the return leg of the Arsenal encounter as reports suggest the knee injury is more serious than expected.
Thank God Rosell has a brain, or else there would've been trouble.