In the winter of 1988, he had given up - literally, given up - on playing quarterback for Colorado and had made his intentions known to anyone, everyone that he wanted to move to running back.
After a bad decision followed by a worse pass in the 1988 Freedom Bowl, which CU lost 20-17 to BYU, Hagan craved no more of the responsibilities inherent in leading a team.
"I was dead serious . . . I was done with quarterback," Hagan recalled this week. "I wanted to be a running back. Give me the ball and let me use my vision."
And above all else, don't ask him to be responsible for anyone but himself . . . just let him be.
But fate intervened in a most unforeseen and soul-wrenching way for Hagan, who now coaches the Buffaloes running backs.
In the end, selfishness was pushed aside by selflessness, and a memento to the transformation that occurred two decades ago hangs on his office wall in the Dal Ward Athletics Center.
Every time Hagan swivels in his chair, he comes face-to-face with a raised and reduced replica of Sal Aunese's No. 8 jersey. It is more than a wall adornment; it brings Hagan face-to-face with what it took 20 years ago to make him a man.
Hagan had thrown a late interception in the Freedom Bowl that cost CU the game. It also cost Hagan almost all of the false bravado that came with the rough territory of his boyhood and a stellar athletic career at Los Angeles' Locke High School.
But his post-Freedom Bowl tantrums about changing positions were silenced that spring when his position coach, Gary Barnett, gave Hagan word that Aunese was suffering from inoperable stomach cancer.
"I went home for spring break and he called me and said Sal was sick," Hagan said.
Barnett had an idea of how badly, and by then he wasn't giving Hagan an option: "He said, 'It's time for you to grow up, be the quarterback and lead this team.'
"Then he said, 'Sal has six months to live.'"
Aunese, 21, didn't last that long. He died on Sept. 23, 1989, leaving Hagan and his CU teammates grief-stricken but also bonded and inspired in a way rarely experienced.
In life, even in death, Aunese drove Hagan. After Barnett informed him of Aunese's condition, Hagan, then a sophomore, had what hardly could be called an epiphany: "All the 'BS' I was trying to put (Barnett) through just wasn't worth it. I just decided, along with him, that it was something that had to be done."
So, Hagan remained at quarterback and became perhaps the school's best ever at the position. He was instrumental in CU's run at national championships in 1989-90 and led the Buffs to Big Eight titles in 1989-91. During that span in conference play he was 20-0-1 as a starter (28-5-2 in all games).
But until being confronted by Aunese's illness and impending death, then committing himself to accepting responsibility, Hagan was headed nowhere.
"Coming from where I came from, we never met as a program, didn't have playbooks, none of that stuff," he said. "All you had was bravado. Then you come in here, to a program with some structure, and you're lost.
"I was able to watch and emulate (Aunese) and it was huge for me - especially for my confidence - because I had lost it."
Even though he doesn't coach the position, Hagan has more than enough credibility to tell CU's quarterbacks "that in order to be good, to be successful, you have to be different.
"Coach Barnett and I met two times a day going over plays, defensive fronts and what they could do to you. It became so routine to me that I could look at a picture or a formation with the defense on the board and I could execute it . . .
"Then once I got on the field, it was like a panoramic view; everything was glaring at me. The game slowed down because I finally knew what I was doing."
But he wasn't home-free yet. The 1989 Buffs believed in Aunese and believed he was to be their quarterback.
"He was going to be a senior, the guy they expected to do certain things with," Hagan said. "And for him suddenly not to be there, and for this freshman to be the guy that they were going to put all their eggs in the basket with . . . it was kind of strange to me and them.
"I knew I had a lot of guys depending on me. When I first got in the huddle, I'd see the guys watching to see if I was vocal, to see if I was attentive, things like that.
"The first practice of spring ball, I busted a long run for a touchdown - and then it was like all the tension went out of the huddle. I think I had everybody believing in me."
The Buffs had a bye on the weekend that Aunese died. Their first game after his death was on Sept. 30, 1989, at No. 21 Washington (CU was No. 5).
In one of the most memorable moments in Buffs football history, CU's players gathered near midfield before the kickoff in Huskies Stadium, collectively went to one knee and raised their index fingers.
It wasn't a "we're No. 1" gesture; it was a team pointing skyward in tribute to Aunese.
"It was totally genuine . . . 'Coach Mac' (Bill McCartney) never tried to give us a pity story, any kind of story to manufacture for our benefit," Hagan said.
"It was just 115 guys playing for each other, playing with one heartbeat. Our goal and our sole mission was to get to the national championship game, because we all knew if Sal was there, it would happen. And we were trying to do it.
"It was amazing how that brought us all together. No one complained about not playing . . . about being hurt . . . about anything. Because anything you had to complain about was secondary.
"It was a brotherhood at its best. It's always hard to remember people, particularly in something like that. You try to forget certain tragedies in your life, but his was . . . I wouldn't say a tragedy.
"His was a way to, I guess, bring men together. It brought us all together and galvanized a community, a state and a program, for sure."