One of the running themes of the 2015 NFL season was the controversy surrounding the league's catch rules. Those debatable rules came up again during Super Bowl 50 on a passing play involving Panthers wide receiver Jerricho Cotchery.

Cotchery was the target of a pass from Carolina quarterback Cam Newton in the first half that the wideout initially seemed to bring in. A review of the play by referees led to a final call of incomplete, however, even though the instant replays of the sequence didn't exactly come down definitively in one direction or the other.

It's just the latest example of the challenges the NFL has had with defining exactly what a catch is. We've seen countless plays over the past couple years, both during the regular season and playoffs, that have required referees to make challenging interpretations of the rules. Now we can add one big instance in the Super Bowl to that list of controversial moments.