Provo • Tanner Mangum’s junior season ended abruptly last fall due to an Achilles injury, but the star-crossed BYU quarterback’s optimism never ceases.

Most observers of BYU’s spring football camp, which concludes on Saturday with a scrimmage at LaVell Edwards Stadium, believe the 21-game starter and most experienced player in the contest to be the Cougars’ starting quarterback has fallen behind the others.

But the self-described “eternal optimist” disagrees, although he hasn’t been able to play in any of the live scrimmages in camp and won’t get any reps on Saturday, either. Mangum is still recovering from the injury he sustained five months ago at Fresno State.

As usual, Mangum sees the positive aspects of the situation, even as freshman Zach Wilson, sophomore Joe Critchlow and junior Beau Hoge have made the most of their live reps in camp.

“This is what spring ball is for,” Mangum said. “It is a chance for everyone to show what they can do. I love it.”

Then Mangum flashes that big smile. He says he’s slightly ahead of schedule and will be “100 percent, for sure,” by the time fall camp begins in early August. By all accounts, he did more this spring than anyone expected after undergoing surgery shortly after the Nov. 4 injury.

“Obviously, it is not the most ideal situation, not being able to do everything,” Mangum said Monday. “Sometimes you just want to be out there playing every single play. You want to get as many reps as you can. But you have to be patient. You have to find ways to get the most out of each rep. So I am back there going through it mentally. I am looking at the defense, looking at what they are giving us, imagining it as if I were in the play.”

Coaches say Mangum has also taken on the role of mentor and cheerleader, continually praising the work of the guys he is competing against for the job.

BYU coach Kalani Sitake is not surprised. Since the day the injury occurred, he says Mangum has never shown anything but positivity.

“There is a tendency to feel like you are getting behind, just because you are not getting quite as many reps as everybody else. But it is what it is. You can’t control that,” Mangum said. “What you can control is your attitude, your preparation, your effort. That is what I am trying to focus on, is bringing the best of my abilities to the practice field every day and doing what I can to contribute every chance I get.”

Quarterbacks coach Aaron Roderick said Mangum’s body of work deserves to be recognized when offensive coaches begin the process of coming up with the quarterback depth chart later this month. He said Mangum hasn’t fallen behind the healthy candidates.

“He hasn’t been able to pull away from the other guys,” Roderick said. “In that way, it has been a disadvantage being out. But I think that he has done enough good things in the spring to show that he understands what we are doing and he gets the offense and he definitely deserves a chance to be in the mix in fall camp.”

The offense Jeff Grimes is installing seems to favor the more athletic QBs in camp — Hoge and Wilson — but the less-mobile Mangum, to no one’s surprise, believes he can flourish in it, too.

“I like to think I could play in any offense — whatever they bring,” he said. “So I feel good about it. I like it a lot. I am happy with the progress I have made throughout spring ball. I am excited about where I am going.”

TANNER MANGUM’S HIGHS AND LOWS

Sept. 5, 2015 • Enters the season-opening game against Nebraska three months removed from his church mission and throws the game-winning touchdown pass.

Dec. 3, 2015 • Named the 2015 College Football Freshman of the Year by the Touchdown Club of Columbus, Ohio.

Dec. 19, 2015 • Directs an offense that commits five turnovers and then scores 28 unanswered points in a 35-28 Las Vegas Bowl loss to Utah.

Aug. 23, 2016 • Loses the starting quarterback battle to Taysom Hill, who was returning from a Lisfranc injury

Dec. 21, 2016 • Leads BYU to a 24-21 win over Wyoming in the Poinsettia Bowl in the only start of his sophomore season.

April 3, 2017 • Posts on social media that he struggles with depression and anxiety and vows to create awareness about the “stigma” surrounding mental health.

Sept. 9, 2017 • Suffers an ankle injury in the waning moments of a loss to rival Utah that sidelines him for two games.

Nov. 4, 2017 • Suffers a season-ending Achilles injury in a loss at Fresno State.

March 12, 2018 • Speaks publicly for first time since the injury and does more in spring camp than doctors and coaches expected, but not cleared for contact drills.