The USFL has a ‘Jeff Fisher Rule.’ It’s an example of spring football league adjusting on fly.

Michigan Panthers head coach Jeff Fisher looks on during a USFL game at Protective Stadium in Birmingham.

Mike Pereira wrote the USFL rulebook, so he’s partial to the previously amended version. That doesn’t stop his phone from ringing with suggestions.

And that’s the beauty of a spring football league, Pereira said – changes can be made on the fly, even between Week 4 and Week 5.

“Honestly, we are a spring league and it is a new league – making the rules, 98% of the rules are NFL. When you’re making some changes like this, there’s no data,” Pereira told USA TODAY Sports last week. “Therefore it’s the kind of league where it can be four weeks into the season and you make the change.”

For example, the Jeff Fisher Rule. The former Tennessee Titans and St. Louis/Los Angeles Rams head coach, currently leading the Michigan Panthers, called a timeout because he wanted to change from a 1-point attempt following a touchdown to a 2-point try.