McCoy had entered his name into the NCAA transfer portal Thursday.
The prospect ranked No. 27 overall in the 2019 ESPN 300 had signed with USC out of Mater Dei High School (Santa Ana, California) in the early signing period in December and enrolled for classes in January.
McCoy, who was the highest-ranked recruit in the Trojans' class, had an opportunity to earn playing time in his first season on campus.
He announced his commitment to USC on Jan. 5. Days later, USC offensive coordinator Kliff Kingsbury left the program to join the Arizona Cardinals.
The 6-foot-3, 205-pound athlete was recruited as a wide receiver (he also played linebacker in high school) and was affected by Kingsbury leaving USC for the NFL. The Trojans still have not named a new offensive coordinator.
Because he already attended classes at USC, however, McCoy will need to sit out the 2019 season or get a waiver from the NCAA to allow him immediate eligibility.