8. K.J. Costello, Mississippi State
K.J. Costello was a highly recruited prospect (No. 47 overall, No. 3 pro-style quarterback) coming out of high school when he committed to Stanford.
He also found a lot of success early in his career as a Cardinal (5,113 yards, 42 touchdowns and only 15 interceptions in 24 games from 2017-18), but an injury held him to only five starts in 2019.
Now, the Coto de Caza (Calif.) native has taken his talents to Starkville to play under new head coach Mike Leach. Considering Washington State quarterbacks have been in the top 10 in passing yards in six of the last seven seasons, that bodes well for Costello having a successful 2020.