Nah, it was a normal back four. He came into the team at the end of October and then was first choice until mid April (so it was almost 6 months
). He started that run partnering Jones and then, once Jones inevitably got injured, Bailly came in for the final month or two. Rojo really should have been sent off twice for bad tackles but otherwise he was very good throughout that period. In fact just looking at the stats for the 17 league games that he started in the central defence we never lost a single match and only conceded 9 goals (never more than 1 goal in a game).
It lasted until the Europa quarter final when he and Zlatan both ruptured their cruciate ligament in the same game and were out for 8 months. Ever since then he's been devastated by injury and fairly poor form on the rare occasion he has played. It sucks and I do sometimes wonder whether he could have been a success if it weren't for that cruciate, but I guess he was fairly injury prone even before then.
Most of his time here has been a waste but I'll remember those 6 months fondly.