Coach Gary Patterson confirmed Wesley's exit, which leaves the Frogs with two 700-yard rushers entering fall camp in August.
Wesley was second on the team with 726 yards and six touchdodwns in 2011.
The Irving, Texas, native was the Mountain West Conference freshman of the year in 2009 and earned all-conference honors in 2010. He was a semifinalist for the Doak Walker Award as the nation's top running back and would have been a senior in 2012.
Junior Waymon James (826 yards, six TDs) and Matthew Tucker (702 yards, 12 TDs) both return for the Frogs.