He flopped in Lyon, how would he be good enough for Juve, though ever since he's moved to Lens in January, he has been the Ligue's best leftback without any competition (yes much better than Grosso). Attacking wise, he is fantastic, his crosses are very good for a defender, he even takes free kicks and corners, decent pace, and a rather good dribbler. He gets caught out of position far too often for my liking though, his defending is just not good enough for a top team imo.
Having said that, he can still improve, i think he is only 23 years old so theres a lot of room for improvement. I'd say he's a slight upgrade over Molinaro.(A huge upgrade offensively though)