"That would be tough to be like, 'No, I'm not staying for this,'" Gebbia said. "This is a special moment in time."
Frost, offensive coordinator Troy Walters and quarterbacks coach Mario Verduzco have had eight practices to work with the quarterbacks, and a pecking order will soon be established.
"The one thing we're going to have to do, and we kind of started it today, is making sure we're getting the guys who are separating themselves more reps so we can get our team ready to play," Frost said Tuesday. "But we have until September to figure out who's going to be the first guy on the field."
Frost said he'll meet with the quarterbacks as well as every other player, to give them a post-spring evaluation.
"Hopefully nobody leaves the program," he said, "but there are only so many guys who can play, so sometimes those things work themselves out."
Rising sophomore Patrick O'Brien backed up Tanner Lee last season and is the only quarterback who has taken a snap for the Cornhuskers. He did not participate in interviews Tuesday.
Gebbia will be a redshirt freshman in the fall and Bunch, a walk-on from Scottsdale (Arizona) Community College, will be a redshirt sophomore. Freshman Adrian Martinez enrolled in January.
Noah Vedral, a native Nebraskan who backed up McKenzie Milton at UCF last year, must sit out this season per transfer rules.
Frost offered no hints about who is leading the competition. The offense requires the quarterback to be a competent runner and passer, to have the ability to make quick decisions and get the team back to the line of scrimmage in a hurry for the next snap.
"I see every one of the guys making some good plays, and then a play that's not so good," Frost said. "Most of the time it's because they're just a little behind mentally, they don't quite understand the concept or they can't quite get there in the time it takes us to snap the ball."
Frost's rundown on the returnees: O'Brien has a strong arm and is doing a good job learning the offense. Gebbia, recruited by Riley for his passing ability, has proved to be surprisingly fast. Bunch is a fast thinker and decision-maker who is a better athlete than Frost anticipated.
Martinez, one of Frost's first recruits, had shoulder surgery in 2017 and didn't play his senior year in high school. Frost said Martinez's arm is 90 percent.
"I don't quite see the steam on the ball sometimes I saw on tape, but he's getting it there," Frost said. "He's looking good. I think he'll continue to improve as he works with Mario and get that last 10 percent."
Martinez said there's camaraderie in the quarterback room, something he didn't necessarily expect considering a competition is underway.
"I call them all close friends," he said. "Noah Vedral, he's been nothing but help to me. He knows the offense in and out already and he's helped us all. Andrew Bunch, Patrick O'Brien, Tristan — they've all been great to me, and I'm thankful for that because it definitely could be another way."