Ghost i read that in Multiplayer you can play as a team on the Single player missions but with your own squad of real players.
Granted it might be a frag fest but i read the big push is to get players to play as a team. Example: Closer you stay with your squad the better you shoot, move,etc.. once you lose more and more of your team you become slower and shoot worse. This is the first SP game i cant wait for. I usually only look for multiplayer games.