Smith, the Buffaloes' top kick returner and one of the team's deep receiving threats, plans to transfer to another school that will enable him to pursue a music career, Colorado assistant athletic director David Plati said.
Wallace, a redshirt freshman, plans to transfer because he was homesick last season and wants to be closer to his family in Bowling Green, Ky.
Two schools that offer the music major that Smith is interested in pursuing are Arizona State and USC. The product of Moorpark, Calif., began making rap demos and CDs during high school and is interested in pursuing that career after he leaves college.
Smith, a junior, finished the 2008 season with 1,987 all-purpose yards. He set school records with 1,568 return yards and 50 kickoff returns, including a touchdown return that helped propel the Buffaloes' season-opening victory over CSU.
Smith also gained 387 yards receiving on 29 catches and added 32 rushing yards last season. He caught 23 passes for 451 yards as a freshman in 2007.
He is also the uncle of heralded Colorado tailback Darrell Scott. The Boulder Camera reported that Smith's departure likely won't damage the school's relationship with Scott, who attempted to talk Smith out of leaving school. Scott was one of the nation's top running back recruits in the 2008 recruiting class but struggled with injuries last season.
Wallace is the third member of the nationally ranked 2008 recruiting class to leave the program, joining linebacker Lynn Katoa and receiver Chance Blackmon.
Tim Griffin covers college football for ESPN.com. You may contact him at firstname.lastname@example.org.