Nico Iamaleava missed Tennessee football's intrasquad scrimmage Thursday due to a stomach illness, so the Vols got a look at plan B at quarterback.

Redshirt senior Gaston Moore worked with the first team, and freshman Jake Merklinger moved into the QB2 spot.

There is no practice scheduled for Friday. Iamaleava is expected to return to the field on Saturday.

Despite Iamaleava’s absence, coach Josh Heupel was pleased with the offense.

“I thought the quarterbacks handled themselves really well here,” Heupel said. “And again, situational football (was emphasized) – being backed up, coming off the goal line, your thought processes, all those things.

“At the same time, everybody inside of our programs has got to continue to grow and get better. And I'm not just talking about Nico. I'm talking about everybody, right? It's a journey.”

It was UT’s second scrimmage of preseason practice. The Vols have three practices remaining before they begin preparations for the season opener against Chattanooga on Aug. 31 (12:45 p.m. ET, SEC Network).

The scrimmage was closed, but Heupel answered questions from reporters afterward. Here are the key takeaways.

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Josh Heupel wants rotation in defensive secondary

Sophomore Christian Harrison and freshman Boo Carter are competing at nickel back after projected starter Jourdan Thomas was lost to a season-ending knee injury.

Walk-on Will Brooks, Middle Tennessee transfer Jakobe Thomas and a few others are competing for a starting safety spot alongside likely starter Andre Turrentine.

And at cornerback, sophomore Rickey Gibson, Oregon State transfer Jermod McCoy, Temple transfer Jalen McMurray and redshirt freshman Jordan Matthews are among the top competitors.

Does the starting lineup matter, or will they all get a chance to play? Heupel signaled that he wants several players to rotate in the secondary.

“I've said it from the beginning of the offseason to our coaches and our players. It can't just be one guy at one position,” Heupel said. “We’re going to have to play multiple guys. It's just the nature of being in this league and the game that we play. I really do like the length, athleticism.”

Dont’e Thornton pushing for second chance

Wide receiver Donte Thornton had a disappointing debut season with the Vols after transferring from Oregon in 2023.

He was hampered by preseason injuries and dropped passes. Coaches said he was slightly out of position playing in the slot. And he suffered a season-ending knee injury.

But Thornton is making the most of a second chance. Heupel said he made some dynamic plays in the scrimmage.

“Dont’e Thornton played extremely well,” Heupel said. “Dont’e has done a really nice job here during the training camp, taking more of a load here over the last few days. (I) really like what we’re seeing from him and his comfort inside of what we’re doing offensively.”

Thornton has spent most of preseason as a backup to Bru McCoy, who’s returning from a severe ankle injury that ended his 2023 season. But UT wants to extend its rotation beyond the starting three receivers, which could put Thornton in the mix.

Offensive line is taking shape toward game prep

Left tackle Lance Heard and left guard Andrej Karic played in the scrimmage after being limited by injuries through much of preseason practice.

It’s a good sign for an offensive line that needs to reach full strength before the season starts.

“As you’re building towards kickoff, all the guys that are going to be playing, you want to continue to sharpen those guys up,” Heupel said.

Heard, an LSU transfer, is projected to start if he’s healthy. Karic faces stiffer competition at left guard from veteran reserves Jackson Lampley and Dayne Davis and redshirt freshman Shamurad Umarov.

DeSean Bishop, Peyton Lewis locked in RB2 battle

When asked who made dynamic plays on offense, Heupel named running backs DeSean Bishop and Peyton Lewis.

They’re competing for the backup spot behind starter Dylan Sampson, or at least until sophomore Cam Seldon returns from a shoulder injury he suffered in spring practice.

Bishop, a former Karns standout, is a redshirt freshman who missed last season due to injury. Lewis is a freshman who missed spring practice due to injury.

Bishop impressed coaches in the first scrimmage of preseason. But it appears Lewis is keeping pace as he learns the offense and adjusts to the speed of the college game.

Adam Sparks is the Tennessee football beat reporter. Email adam.sparks@knoxnews.com. X, formerly known as Twitter@AdamSparks. Support strong local journalism by subscribing at knoxnews.com/subscribe.

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This article originally appeared on Knoxville News Sentinel: Tennessee scrimmage: Nico Iamaleava out, Dont'e Thornton flashes