i used the editor to put the right players in the france squad, but Rio Mavuba is unable to be selected for some reason, i cleared the france team, and added the 18 players by hand. whats wrong with it?

is it because he is 20 years old?, is it because he has a second nationality? (he's first 1 is france the 2nd one i can't remember sorry), if somebody can help me sort this out pls!