After its use in the Philadelphia Eagles win over the Kansas City Chiefs at the weekend, the debate surrounding the legality of the "Tush push" has re-emerged. Before the season, the vote to ban the play failed, allowing teams (primarily the Eagles) to use the play.Former Pittsburgh Steelers coach Bill Cowher made an apperance on "The Dan Patrick show" on Monday, where he gave his take on the play."I've been against the play (Tush Push) for two years, I've made my feelings quite known. It's not a football play. It's a scrum.And they had that in rugby, Dan. They eliminated the scrum because it wasn’t safe. But we keep it in the NFL. We’re going to have to wait for some kind of catastrophic injury to change it.”The main argument concerning banning the Tush Push comes from the notion that teams that are defending against the play can not do so without committing a penalty. This means that the Eagles can not fail with this play and are almost guaranteed a touchdown. As we saw in the Eagles-Chiefs game at the weekend, this can be the difference between victory and defeat.Cowher's reason to ban the play comes less from a competitive advantage point of view and more from a safety perspective. He likens the play to a scrum in rugby union. This is a play that has had notable changes over the years (as our knowledge of sports related brain injuries have increased) with the play being made significantly safer. The most notable change is that the two "packs" do not forcefully come together before the ball is put into play.The same cannot be said for the tush push, which still sees numerous players barging into each other in a very small space.As of writing, there have been no recorded injuries concerning the tush push play, and there is currently scientific research from the University of Rochester being completed on how to make this play safe.However, as with all safety related decisions, where is the line drawn. Unfortunately, this is normally when someone has become seriously injured as a result of the play. Cowher is worried that the NFL is going to wait for this moment before making any decision on the future of the play.Are the Eagles cheating while using the tush push?Eagles coach Nick Sirianni has addressed his team's use of the play during their win against the Kansas City Chiefs. Philadelphia used the play on seven occasions. Later analysis found that the Eagles may have committed a false start on a few of these. Sirianni said the following to NBC news about this:"I think that the one clip I saw of it was slowed down so much that I'm not sure you can see that to the naked eye. I mean, it was slowed down so much, and I get how we can manipulate things and show things like that, but it was slowed down so much, it was like, 'Right!'To the detractors, this will only provide them with more evidence on why this play should not be allowed.Not only is it potentially very unsafe (where the risk of injury is likely to be greater than the reward), but the Eagles may be gaining an unfair advantage in using this play.