I was fine with TFM as I thought maybe a fullback who could attack might help, but why on earth change the CB?
Defenders innit! Think you get a secret bonus point when you change over 50% of your back line.
More seriously, I've not a feckin clue. Also instead of bringing on TFM.. Why not bring on James or Lingard and put them there or put McT there and bring on Mata?