Maybe he'll play as long as Cafu after all, his tackles stats are record high this season - 3.8 per game, he also made 7 assists already and now even his crosses are getting better...
After having thought about it, I can see him being used as a midfielder soon. That article i_bleed_blaugrana linked to in the transfer rumours thread has some good points. He has the technique, vision and work rate for the position.