Del Rio, the son of Oakland Raiders coach Jack Del Rio, threw for 141 yards last season, appearing in three games as backup to senior starter Sean Mannion. He was considered one of Oregon State's top options at starter now that Mannion has graduated.
New Beavers coach Gary Andersen, who took over after Mike Riley's departure for Nebraska in December, said in a statement Thursday that Del Rio decided it was time ''to start a new chapter in his life.'' Del Rio in turn thanked Oregon State.
Del Rio was a walk-on at Alabama and redshirted in 2013 before transferring to Oregon State for the 2014 season.