After a first season with Barca B, the fullback is being tipped for first team action this term.
Former Barca midfielder Keita, 39, is a fan and believes Wague can handle the expectations.
"Moussa Wagué is a young player, and playing Barça is always an honor," said Keita.
"I saw him play a few games and he has quality. I hope he has time to confirm his potential here because Barça is the biggest club in the world and, for a great day, it's a pride to play here."