The defence was a bit of a mess when he joined, we had our longstanding left back issue which didnt help the lad being the left CB and there just seemed to be too many forwards who Mangala just couldn't get a grip of. He was fine with a defender back up against him e.g. Costa but anyone looking to run it down the channel or turn him and he was caught on his feet. He showed some great examples of recovery pace a few times but can't keep relying on that.
At Porto he stood out and I don't think it was a bad decision to buy him, just didn't work out. Under Mancini I think he would have been fine with how our team setup and a fit Kompany alongside him every game.
On more than one occasion we would see Otamendi or Demichelis flying up the pitch, Kolarov/Clichy nowhere to be found and Mangala stood by himself. Didn't happen under Mancini very often and Mangala would have just been seen as an upgrade on Lescott, a big physical presence but can still win the ball and pass it into midfield. He is no Laporte on the ball but he is certainly not as bad as Lescott was.