It would have been his only chance if he were the only defensive player on the field, but there were other Cowboys running from the middle of the field toward the play, and forcing the receiver back to the middle of the field would have given them a chance to help with the tackle. The way he played it he was alone on an island.
No, the other defensive players were not deep enough to help. I just reviewed it on the All-22.
I've said before that I wish I had a simulator that would show what-if scenarios using real video as the baseline (i.e. What-if Tate had gone outside).
His only real mistake was that he needed to be about 6 inches closer to the sideline when he broke-down to wait for Tate to commit inside/outside.
The fail on that play was by the CB. The CB has to at least slow down the WR even if he allows the catch.
In the Kris Richard base coverage and most variations, a CB is responsible for the area near the sideline regardless of depth. It is a vulnerable spot in the KR scheme. If the WR is between a CB and the sideline, the general expectation in the KR scheme is that that CB can handle the coverage without help in that area near the sideline (i.e. Worst case expectation is that the WR catches the ball and is pushed out of bounds or cuts back inside at the point if the catch. The one thing the CB can't do is allow the WR to run down the sideline after the catch).
