Wittek plans to graduate in the spring and has two years of eligibility left. He would be able to play immediately because of an NCAA rule that allows graduates the freedom to transfer without losing a year of eligibility.
"I had talked to coach [Steve Sarkisian] a couple of times," Wittek told the Los Angeles Times. "What it really came down to was a feel for me. ... Getting my degree from such a great university will mean a lot, and ultimately, allowing me to play right away with two years to play was the best way to go."
Wittek was locked in a quarterback competition with Cody Kessler last spring for the right to replace Matt Barkley.
That competition eventually spilled into the 2013 regular season, and Wittek and Kessler spent the first two games splitting time before then-coach Lane Kiffin settled on Kessler as the starter.
Wittek replaced the injured Barkley at the end of the 2012 season, dropping the regular-season finale to Notre Dame and the Hyundai Sun Bowl to Georgia Tech.
In five appearances this season, he completed 14 of 26 passes for 212 yards with no touchdowns, an interception and an adjusted QBR rating of 5.8 out of 100.
He finishes his USC career 50 of 95 for 600 yards with three touchdowns and six interceptions.
Kessler, Max Browne and Jalen Greene are the remaining scholarship quarterbacks on the USC roster. The Trojans finished the 2013 season 10-4 and ranked 19th in the AP poll.
ESPN.com's Kevin Gemmell contributed to this report.