For their September 29th home game against the Arizona Cardinals, the Tampa Bay Bucs intended to bust their creamsicle throwback unis. The NFL has thrown a monkey wrench in those plans with another of their inane rule changes.
It's not because the uniforms are horrendous. The NFL no longer allows teams to wear more than one helmet per season.
Via Buccaneers.com:
The league-wide guideline, which requires players to use the same helmet for all games during the season, was recently implemented based on the strong recommendation by the NFL’s Head, Neck and Spine Committee as well as the Player Safety Advisory Panel.
There's no explanatio given as to why an alternate helmets are so unsafe, but Roger Goodell seems to have been scared straight by the threat concussions and concussion-related lawsuits have posed on the future of his league.