Stopper knows little about the Moroccan
The Gunners striker could be in line to start against Barca at the Nou Camp on Tuesday night, but Robin van Persie is likely to play if he passes a fitness test.
"I don't know him, but if he is at Arsenal he must be good. I will be wary of him," Valdes told Le Parisien.
"We will wait for the team news to be sure that Van Persie won't play. Apart from the coach of Arsenal, nobody knows who will play."
Marouane Chamakh to score anytime (Barcelona - Arsenal) @ 7/2