Colorado State coach Mike Bobo criticized Pac-12 officials after Friday's season-opening loss to Colorado in Denver, saying the rivalry game is too big not to have officials from a neutral conference.

The Rams fell 52-31 to the Buffaloes, their fifth straight loss in the Rocky Mountain Showdown, which has been played in Denver since 2010. According to the series contract, the home team provides officials for the game. Colorado served as the home team Friday, so a Pac-12 crew worked the game.

"I don't understand it. It's too big a game not to have neutral refs," Bobo told reporters.

Bobo took issue with a fumble ruling against Colorado State early in the second half, with the Rams trailing 24-21. Officials ruled that Colorado safety Aaron Maddox jarred the ball loose from Colorado State's Marvin Kinsey Jr. before Kinsey hit the ground. A replay review upheld the ruling, and Colorado scored soon after to take a 10-point lead.