FORT COLLINS, Colo. — After his team lost for the 13th consecutive time, Colorado State coach Sonny Lubick says he has been thinking about retiring at the end of the season.

Lubick, 70, is in his 15th year at Colorado State and is the most successful coach in school history, winning or tying for six conference championships and taking the team to nine bowl games.

But the Rams are 0-6 this year and have the second-longest active losing streak in the nation, behind Florida International's 18 straight. Colorado State lost to Air Force 45-21 on Saturday night.

Lubick said Monday the losses are forcing him to think about what he might do when this season is over, including whether to retire.

"Yeah, those thoughts go through people's minds," he said.

Lubick, who makes about $500,000 annually, is under contract through the 2009 season.

Colorado State athletic director Paul Kowalczyk said he has no plans to talk with Lubick about his future until the season ends.

"It will be just like last year; we will sit down at the end of the season to discuss things," Kowalczyk said.

Kowalczyk acknowledged some fans are getting restless.

"The bottom line is that we all want the same thing: a successful program," he said. "I think it's good that this is our common goal and that everyone is going to work hard to make the program successful."