Stanford quarterback K.J. Costello has entered the transfer portal after the Cardinal's disappointing 4-8 season, a source confirmed to ESPN's Tom VanHaaren. Costello will be a graduate transfer.
Beginning the season as the starter, Costello completed 102 of 167 passes for 1,038 yards and six touchdowns. He was intercepted three times, finishing with a rating of 121.6.
A 6-foot-5, 222-pound senior, Costello last played in a Nov. 9 16-13 loss at Colorado. He threw for 245 yards with one touchdown and one interception in that game.
Davis Mills, who started the remaining three games for Stanford, all losses, ended up with 1,960 passing yards, leading the team.