A day after SI's Pete Thamel reported that a source had indicated Oklahoma State redshirt freshman quarterback Brendan Costello would be entering the transfer portal, the Californian made it official on Thursday.
Costello's departure leaves OSU with just two scholarship quarterbacks in returning starter Spencer Sanders and early-enrollee freshman Shane Illingworth. However, they will be joined in June by JUCO transfer Ethan Bullock.
Walk-ons Shaun Taylor and Peyton Thompson round out Tim Rattay's QB corps for the fall.
Costello redshirted during the 2019 season.