UCF's quarterback room just got a big shakeup.

Thomas Castellanos, the presumed backup to John Rhys Plumlee, announced Thursday he has entered the NCAA Transfer Portal.

Castellanos was the first high school recruit to commit to UCF head coach Gus Malzahn in March 2021. A big selling point was Malzahn's vision in Castellanos as a quarterback. Some schools such as Florida State viewed him as more of an athlete that could play running back or wide receiver.

Castellanos arrived on campus in January 2022 and spent last season as the No. 3 option behind John Rhys Plumlee and Mikey Keene. Castellanos appeared in four games during the regular season, the maximum number to maintain his redshirt. His most extensive action came in the 70-13 victory against Temple. Castellanos was a perfect 6-for-6 passing for 60 yards while rushing three times for 88 yards including a 37-yard touchdown run.

The redshirt plans changed when UCF played in the AAC Championship at Tulane. With John Rhys Plumlee hobbled with a bad hamstring and Mikey Keene electing not to play to preserve his redshirt, Thomas Castellanos was called into action.

After Plumlee was initially ineffective and clearly struggling with his injury, Castellanos played most of the second and third quarters before Plumlee re-entered the game. Castellanos finished 2-8 passing for seven yards.

This spring, Castellanos was the clear backup to Plumlee but also ran with the first team at times. He started the spring game while Plumlee was still on the baseball diamond. His highlight was a 29-yard touchdown pass to Dionte Marks.

Castellanos seemed full of confidence when he ended his post-spring game press conference with this comment:

"Hopefully I do turn out to be QB1 but if not, hey, I'm going to be No. 2 and I'm the future of this place so Charge On."

Castellanos' departure leaves UCF with just two scholarship quarterbacks: Plumlee and former South Florida transfer Timmy McClain. A third, signee Dylan Rizk, arrives this summer.