Penn St./FSU Safety?

[shave-tail]

First of all, I don't have a dog in the race so this post is only for discussion. When FSU was on their 1 yard line and the ball was handed off, there was a push by the Penn St. defensive line. The ball carrier was out of the end zone when he was contacted, however I don't think his forward momentum was stopped by a tackle but more by the surge up the middle. After a step or 2 of retreat he was tripped and went down in the end zone. I my arm chair...got to see several replays opinion, I think this should have been a safety. Any other thoughts are welcome on this.