Maybe as a RB against second rate teams in the league but as a CB not in any match. Has no ball handling ability, not intelligent enough to make up for lack of size and strength. I'd take Marchisio over him as CB any day.
He's a destroyer, no sign of intelligence yet. Put him in to get the ball back that's it.
How do you know he's not intelligent enough? His defensive work has been spot on, and I rarely see him out of position. Don't confuse lack of technique and passing ability as lack of intelligence. He's got plenty of strength as well, and you don't need to be 6'3 to play CB. Just look at guys with similar builds like Sergio Ramos and Thiago Silva