That's because we only have 3 men in there. We often come up against 5 so we are already outnumbered which is why our fullbacks are asked to push up. Then all the opposition do is drop the ball in behind them and thus drag the less mobile centre backs out. Greer is often caught out like thisLike the look of this. Ince or Holla drop back to make the 3 but that is when our midfield look weak and depleated and we get overun.