The toughest moment? Not the reality that his junior season was over, or that the school's Heisman Trophy campaign was short-circuited or that his teammates kept pursuing a Mountain West division title without him.
No, it was all more practical than any of that stuff. "The most humbling thing was not being able to walk," he said.
The biggest source of encouragement? Not necessarily his parents, coaches, athletic trainers or teammates, although they've certainly helped. His best example is Jennifer Flynn, a USU soccer player whose senior season was complicated by injuries, before she delivered a penalty kick that helped the Aggies edge New Mexico in the Mountain West tournament.
"I don't think she knows it," Keeton said, "but that was a very good motivator for me."
In Keeton's case, nearly six difficult months are behind him and an intriguing senior season is ahead. He's encouraged, knowing what he's overcome just to reach Tuesday's stage of his return, standing and throwing to receivers who were running routes during an early morning practice at Romney Stadium, in the middle of USU's spring drills.
"You've got to find a way to see one bright thing, one good thing that's going on, and try to focus on that," he said. "If you can just keep your mind on that one positive thing for that one moment, eventually you can get yourself to the end point."
He bonded in rehabilitation with USU running back Joe Hill, who injured his knee the previous week at San Jose State.
They've supported and pushed one another, besides watching their teammates play road games without them.
Keeton is proud of the attitude he's displayed through it all. "Somehow, people are telling me I'm encouraging them," he said. "I never knew that tearing an ACL would bring so many positive things. … I guess I had the bigger picture in mind. I know a lot of people just expect me to play football and that's it, but we've got a lot of things going on outside of it. That's one of the things I just kept in mind the whole time."
As Keeton details how he transferred his football energy and competitiveness into academics, weightlifting and film study, he sounds a lot like Damian Lillard. The former Weber State guard recovered from a broken foot to become the No. 6 pick in the 2012 NBA draft.
"We know that he's not going to cheat us," said USU offensive lineman Kevin Whimpey. "We know that he's going to work as hard as he can."
USU coach Matt Wells believes Keeton is more motivated than ever, "because there's people out there that doubt him," he said.
Known for being relentlessly upbeat, Keeton has gone through "a range of emotions," said Wells, who's close to him. They were together from the start in 2011, when Keeton arrived as a freshman and Wells joined Gary Andersen's staff as the quarterbacks coach.
What's next? Anyone would wish for Keeton to have a fulfilling senior season. Because of injuries, he's started and finished only 25 of a possible 40 games in three years. And some of his most memorable performances have come in narrow losses to Auburn, Wisconsin, BYU and Utah.
In so many ways, Keeton deserves some better endings in 2014, when obvious checkpoints dot USU's 2014 schedule including the Aug. 30 opener at Tennessee, an Oct. 3 visit to BYU and a Nov. 29 game at Boise State.
"If anything, I want to improve from where I was more touchdowns," Keeton said, and then he smiled and added a clarification. "More timely touchdowns."
Twitter: @tribkurt Season cut short
Until injuring his knee in the first quarter of the sixth game, Utah State quarterback Chuckie Keeton was having a remarkable 2013 season. His game-by-game statistics:
Co-Att Yds. TD Int
Utah 31-40 314 2 0
Air Force 32-40 360 5 1
WSU 19-25 249 5 0
USC 21-39 179 2 0
SJSU 29-42 260 3 0