Mannion beat out Katz and Vaz for the starting job when the other two suffered injuries in practice.
"Sean took all the turns for about a week and separated himself at that point by a bit, not by a bunch," Riley said. "Cody has great character and he always stayed ready. He has always been involved and stayed confident. He knows he can play and he stayed ready to go and that is credit to him."
Vaz, a 6-1 junior, certainly has the attention of the Utes who know they must get to him if they are to have a chance at stopping Oregon State's passing attack.
"They didn't modify the offense at all for him from my perspective," Utah coach Kyle Whittingham said. "Sometimes you change things for an inexperienced quarterback but he is doing a nice job running that offense."
Riley said he got to know Vaz well last year since Vaz was on the sidelines, which led to more interaction.
"He is a neat guy," he said. "He is cool and calm and always confident."
Giving him respect
Whittingham said he has a lot of respect for the Oregon State coach, putting him up there with former Colorado State coach Sonny Lubick and former Air Force coach Fisher DeBerry as coaches he admires.
"He is really the dean of the Pac-12 coaches," Whittingham said. "He is a guy I believe who has a wealth of experience and knowledge and I have the utmost respect for him. In the meetings I hang on every word he says.
"He is a phenomenal football coach," he added. "They were down a bit last year but he has them right back up and playing great football and he has that thing going right now."
Only two punters in Pac-12 history have averaged better than Utah's Sean Sellwood's average of 48.4. Kirk Wilson averaged 49.3 yards in 1956 and USC's Tom Malone averaged 49.0 in 2003.