Game auto sub outs impact players

[Arronwy]

I noticed in the 4th qtr of every game the game subs out all my impact players(except the QB). I can't sub the back in no matter what I do. I tried to make them the 2-4th on the depth chart but they still wont' be allowed to go in. In formation subs I manually select that player and the game just ignores it and won't let me switch them. WTF is going on with this?

Edit: It seems like it just subs out random starters in the fourth. This game wasn't even a blow out it was a one possession game and I was playing with half my second team and without my best players.