“The only unfortunate part is that I haven’t played him enough," Riley said Tuesday.
Oregon State visits Provo to face an independent BYU team that is 4-2 but facing quarterback issues of its own.
Cougars coach Bronco Mendenhall announced Monday that freshman quarterback Taysom Hill is out for the season after injuring his left knee in BYU’s 6-3 victory over Utah State last Friday night.
Hill was standing in for senior quarterback Riley Nelson, who missed two games with what he described as “back fractures."
Nelson, who has passed for 754 yards and five touchdowns with five interceptions, is expected to play against the Beavers on Saturday at LaVell Edwards Stadium.
Mendenhall learned of Oregon State’s quarterback situation just before the start of practice on Monday.
“Who knows what the fallout is?" Mendenhall asked. “You have a good offensive system in place that’s very consistent from year to year. How that will be tailored all of a sudden to a new quarterback, I’m not certain. We’ll prepare for what we know and then adjust to what we don’t know or what we see on game day. That’s really the best we can do."
Mannion’s injury was a surprise, even to Riley. The 6-foot-5, 212-pound sophomore showed no sign of it during the Beavers’ 19-6 victory over Washington State, when he was injured on a handoff but did not leave the game. He finished with 270 yards passing and a touchdown.
On Monday morning, just as the team was about to go into a meeting, the news hit.
“It was a total shock," Riley said. “The doctor and the trainer came running down the hall. So I knew it wasn’t good."
Mannion is expected to have surgery to repair meniscus damage in his left knee as early as today. His status will be week to week following the procedure.
Mannion was averaging 339.5 yards passing per game, second in the Pac-12 and sixth in the nation. He has passed for 1,358 yards with seven touchdowns and four interceptions this season. He is sixth on Oregon State’s career list with 4,686 yards.
Vaz grew up in Lodi, Calif., and played at St. Mary’s High School, where he was 24-5 in two seasons as the starter. He was the Stockton Record’s player of the year his senior season.
Vaz’s backup going forward will be walk-on redshirt freshman Richie Harrington.