Garretson played in 13 games over the past two seasons, filling in for starter Chuckie Keeton after he suffered season-ending injuries both years. Garretson missed the last seven games of the 2014 season with a wrist injury. Keeton was granted a medical waiver for a fifth year of eligibilty.
Garretson will be a walk-on at Oregon State with two years of eligibility remaining after he sits out the 2015.
Garretson completed 67.4% of his passes for 1,140 yards with eight touchdowns and three interceptions last season. He was named Mountain West Offensive Player of the Week after throwing for 321 yards and three touchdowns in a win over BYU.
Oregon State must replace quarterback Sean Mannion, who threw for 13,600 yards in four seasons for the Beavers before being drafted in the third round of the NFL draft by the St. Louis Rams.
- Dan Gartland