Wisconsin's Alex Erickson had a thrilling punt return for a touchdown against Northwestern. He shrugged off a slew of Wildcat gunners, all of whom should've brought him down, and took the ball all the way to the house. It invigorated a Wisconsin team and crowd that had felt lifeless after Northwestern shut them out in the first half.

And then the refs called it back.

Erickson had waved his arms to keep his teammates away from the bouncing punt to avoid a turnover. The refs ruled this was an "invalid fair catch signal."

An "invalid fair catch" prevents the player from advancing the ball, but also doesn't protect them from getting tackled, which is why the Wildcats weren't flagged for fair catch interference when they tackled Erickson. It's the worst of both worlds.

By the rulebook, what Erickson did is, in fact, outlawed. Technically, any waving besides a single arm waved above the head is an "invalid signal."

Valid Signal ARTICLE 2. A valid signal is a signal given by a player of Team B who has obviously signaled his intention by extending one hand only clearly above his head and waving that hand from side to side of his body more than once. Invalid Signal ARTICLE 3. An invalid signal is any waving signal by a player of Team B that does not meet the requirements of Article 2 (above.)

FOX refereeing expert Mike Pereira agreed with the call:

After an invalid signal, the play is dead when possessed but the receiver does not get protection. — Mike Pereira (@MikePereira) November 21, 2015

But that doesn't allow for common sense. We see return men wave their teammates away from a hot ball all the time. Of course, most of the time, they don't end up picking the ball up and running with it. But it's pretty clear that the "get away" signal is not meant to be a fair catch.

This call is meant to eliminate players attempting to deceive the punting team into not tackling them. That's not what happened here.

Nobody on Wisconsin thought Erickson signaled for a fair catch. They kept blocking. Nobody on Northwestern thought Erickson was signaling for a fair catch. They kept trying to tackle Erickson. Pretty much only the refs interpreted it this way. The rules probably should allow for what Erickson did.

Anyway, instead of getting a touchdown, the Badgers went backwards seven yards and punted. In a close game, this call could make the difference.