Allen, 6-feet-5, 226 pounds, completed 18 passes in three seasons at Oklahoma. He is eligible to participate immediately because he is graduating from Oklahoma and has one year of eligibility remaining.
"Syracuse is a great decision for me because coach [Scott] Shafer and his staff have given me an opportunity to come in and compete for the starting job," Allen said. "All I want to do is compete and make Syracuse a better football team, however I can do that."
Allen passed for 2,315 yards and 22 touchdowns as a senior at Alamo Heights High School in San Antonio and considered schools such as Oklahoma State, Kansas State, Purdue and Colorado.
Syracuse has experience with this scenario as Greg Paulus once played one season after earning his degree at Duke.