The difference between a legal hit and an illegal one in football is often determined by inches and seconds.
A proposed rule change by the NCAA could make those inches and seconds even more important in college football.
A player who delivers a hit to the head of a defenseless opponent could be kicked out of the game next season under an NCAA proposal that took a step forward Wednesday.
Consider this another high-profile step in the universal effort to make football less dangerous and cut down the risk of head injuries. The future of football became a hot topic again in the lead up to the Super Bowl when President Barack Obama said if he had a son "he'd think long and hard" before letting him play the game. He also voiced concern about whether the NCAA was doing enough to help college players deal with long-term health issues that come from playing football.
The NFL has been cracking down on helmet hits in recent seasons, handing out more frequent fines and even suspensions. But those penalties are determined days later, after the play has been reviewed.
Under the NCAA Football Rules Committee proposal, video replay will be used to determine the ejection part of the penalty, but that call will be made immediately.
And that's troubling to some coaches.
New Temple coach Matt Rhule, who spent the past last year as an assistant with the New York Giants, said it might be asking too much of replay officials to conduct a thorough review of a complex play that could result in a player losing the right to participate.