After consulting with doctors regarding the risk of further concussions, Threet announced in February he would not return for his senior campaign as a Sun Devil.
"Ultimately it was my decision," Threet said. "The doctors never said (coming back) was impossible. They gave me the information they had about what was best for me. Over the course of time, I felt like (retiring) was the best decision."
Last season, Threet took a majority of the snaps in first-year offensive coordinator Noel Mazzone's fast-paced offense. Threet threw for 2,534 yards and 18 touchdowns. If healthy all season, Threet likely would have become the third ASU quarterback to ever throw for 3,000 yards in a season.
While Threet's playing days are over, it appears his football career may just be beginning. Threet never really left the Sun Devils, as he announced he would help the team as an undergraduate assistant coach at the same time he announced his retirement from playing.
On Saturday, Threet wrapped up the first spring football session as a coach, helping prepare junior Brock Osweiler, redshirt freshman Taylor Kelly and true freshman Mike Bercovici to fill his shoes at quarterback.
Threet will also help coach the trio this fall.
"(Coaching) was a mutual decision between me and the coaches," Threet said. "They wanted me to stay on, but at the same time, I wanted to be a part of the team also. Being out here and still being able to work with the guys and help them improve, if I can, has definitely helped."
Coach Dennis Erickson said he is happy Threet was able to share his experiences from a year ago with the current batch of quarterbacks.
"It's great having him here," Erickson said. "He can talk to the guys about things he learned last year, so that makes a big difference."
Regardless of injury, Threet has been shaping up as an ideal coaching candidate the past few years.
After starting his career at Georgia Tech in 2007, he transferred to play one season at Michigan in 2008, before coming to ASU in 2009. In total, Threet has played or practiced under six offensive coordinators in his college career. Plus being a smart guy doesn't hurt – Threet was valedictorian of his high school class in Adrian, Mich.
Kelly, who was roommates with Threet last season, said he could see Threet coaching as a profession.
"He's got a lot of intelligence in him, and he knows what he's talking about," Kelly said. "I think he will be a huge asset to our quarterbacks because he played in this offense last year. He can tell us what he saw, and that's good."
Threet said he still suffers from headaches, but they are getting better all the time.
He added that while staying with the Sun Devils as a coach has proved therapeutic in his transition from being on a player, it may give him a head start on a future coaching career.
"I think this fall will give me a good idea as to my future direction, if it will involve coaching or not," Threet said. "But I'm definitely thinking about it."