During Sunday's NFL game between the Seattle Seahawks and the Philadelphia Eagles, Seahawks quarterback Russell Wilson makes a pretty nice move. After taking the ball and running with it, he makes a quick pitch off to the side while faking out the defender. Looks pretty cool, but it probably wasn't legal. In the NFL, once you cross the line of scrimmage you can only toss the ball backward. This should have been a penalty for an illegal forward pass, but it looks like he got away with it.

But was it really a forward pass? Yes. It's not so easy to tell if you watch this in real time, but going frame by frame it's much clearer. Wilson tosses the ball when he is at the 46 and a half yard line. The running back (Mike Davis) catches it at 47.5 yard line. That's a pass that goes 1 yard forward—so a forward pass.

Just to further drive home the point, I can use my favorite video analysis techniques (using Tracker Video Analysis) to get the position of both Wilson and the ball as he runs down the field. Check this out.

In this plot, the red data shows the position of Russell Wilson in the direction of the field (x-direction) and the blue data is the position of the ball. Just for fun, I can also fit a linear function to the data (for straight parts) to get the velocity in that direction. During the toss, Wilson is running at 4.55 m/s (10.2 mph) while the ball has an x-velocity of 1.27 m/s. But since both the ball has a positive x-velocity, it is indeed a forward pass. Illegal.