Exum has been ruled out of the Alabama game. With Manning gone, Virginia Tech will now have true freshman Kendall Fuller play both cornerback and nickelback.
Coach Frank Beamer's official website announced the Manning departure Sunday afternoon.
Manning had his ups and downs with the Hokies. Last year, he considered leaving the team before Beamer and defensive backs coach Torrian Gray persuaded him to stay.
Facyson and Fuller have drawn high praise from the Virginia Tech coaching staff. Facyson has been enrolled since the spring and turned heads during spring practice. Fuller was the top recruit Virginia Tech signed in February. His brother, Kyle, starts at the other cornerback position.