Lots of mixed comments about this lad.
From what I've read so far - he seems to be a decent player, but not a great one, especially as a centre back. I also find his behavior on and off the pitch quite worrying, especially all those stupid fouls and cards, is that something our defence (with all experience gone) really need right now?
The funny part is that we wanted to sign a crock Vermaelen before moving to Rojo, so he's a plan B of plan B, as we probably wanted Hummels in the first place.
On the other hand, he was in the WC 2014 All-Star team based on Castrol Index and played as a left-back.
He's not a bad player then, as of now he's an instant upgrade to what we have, but if he's at level we should aspire as a team who want to be back at the top level - time will tell. Hopefully LVG can do some magic and make something out of him.
We still need another defender, and I mean quality one - but probably not in this transfer window.