NORMAN — The moment was always going to come when Jackson Arnold would become the Sooners' starting quarterback.

When Dillon Gabriel announced last week that he was transferring to Oregon, combined with his absence at Tuesday's practice, it became clear that Arnold's time has come. His first official start will come in the Alamo Bowl.

It's been a pretty big change.

"(You still have to) practice, but as a backup it does kind of suck a little bit coming out knowing you're not the guy and you're taking less reps," Arnold said during Tuesday's media availability. "And there's obviously a bigger excitement level coming out, knowing that you're the guy and you are going to go out and play.

"I'm super excited. It's obviously a great opportunity for me. You know, being a freshman and getting some real experience before experiencing the SEC next year, I'm super pumped up for this opportunity."

Fortunately for Arnold, he's got some time to prepare, and he learned a lot from Gabriel. The Sooners are allotted 15 practices to prepare before the bowl game against No. 14-ranked Arizona, which is set for Dec. 28. It won't be Arnold's first time on the field, as he's appeared in five games this season including at BYU, when he started in the second half after Gabriel was ruled out at halftime due to injury. Arnold took every snap over the final two quarters, completing 5-of-9 passes for 33 yards while adding 24 yards on the ground. But that was unexpected playing time for Arnold, who now has two weeks to prepare for his first collegiate start later this month.

The bowl practices are also crucial in getting Arnold comfortable with new offensive coordinator and quarterbacks coach Seth Littrell. Arnold's relationship with Littrell began when he was hired as an offensive analyst during the spring, and now the duo has time to develop a rhythm as quarterback and play caller.

Arnold acknowledged that former offensive coordinator Jeff Lebby's departure to Mississippi State was a big change, but Littrell's elevation to offensive coordinator was a huge confidence boost.

"It's hard for coach Littrell because we're still going off of (former OU offensive coordinator Jeff Lebby's) plays and his terminology right now," Arnold said. "So I won't see Coach Littrell kind of take over and implement his style and stuff until the spring but so far, I've seen him step into a more vocal role, especially in our meeting rooms. That was something I was very curious to see, him coming from an analyst to the position as OC now, I was curious to see that transition and I think he's stepped up and been a more vocal leader for us.

"I've been close with Coach Littrell since he got here, a constant communication since he's got here. He's helped me develop as a player, even while not in the OC role. It's been super great to get to know him and I'm super happy he's in the OC role now."

It's also a big opportunity for Arnold to get more comfortable with his teammates. As the back-up quarterback he didn't see a ton of opportunities in practice, but now he has time to build chemistry with the starters.

The Sooners have been focused on keeping things consistent and not making significant changes to the offense before the bowl game. But there's a level of excitement about Arnold stepping into the starting role.

"I’ve watched Jackson since he’s been here," OU receiver Jalil Farooq said. "I’ve watched him grow up. Him stepping up in the room, I’m very excited to see him play in the bowl game. I can’t wait until he showcases his talent. He’s a great dude, a great leader. He can sling it.”

Even the defensive players are excited, like veteran linebacker Danny Stutsman.

“He’s a competitor," Stutsman said of Arnold. "His instincts are second to none. He’s a great player. We already know what he does. We’ve seen the film. He’s a great leader. We know he’s gonna step into that role starting with this bowl game, which is a great opportunity for him. There’s nobody I’d like better to lead this team... I think he can lead even better than Dillon did. That’s just who he is.”