The heat of Georgia Tech’s season opener, combined with playing 26 snaps in the second quarter alone, was a withering conditioning test for the Yellow Jackets’ defense. It helped outside linebacker Quayshawn Nealy, among others, realize he needed to improve his fitness.

“The conditioning level, especially off of last Saturday, it wasn’t where it needed to be,” he said. “Guys were definitely tired. We had guys cramping up.”

Duke, Tech’s opponent Saturday, will come after the Yellow Jackets with an up-tempo, no-huddle offense. Much of the reason for the proliferation of no-huddle offenses is their debilitating effect on defenses. Elon also ran a no-huddle.

“It was good for me to be out there because I definitely need to be in game shape,” he said.

Nealy wasn’t quite staggering around the field. He recorded eight tackles and a pass breakup and was chosen the team’s defensive player of the game. Still, Nealy used the open date to get in some extra running and time on a stationary bike. Part of the defense’s fatigue resulted from the second quarter, when the Tech offense was on the field for four plays. The Tech defense went on the field for two consecutive series when linebacker Tyler Marcordes ended a 12-play Elon drive by returning an interception for a touchdown.

The weather should help the Jackets on Saturday. The forecast calls for a high of 75 degrees.

Third-down challenge: One way Tech's defense can limit its fatigue is by stopping Duke on third down. Defensive coordinator Ted Roof has made it a priority this week after Elon was 6-for-16 in converting third downs. Improving defense on second down is part of it. Becoming more adept in the scheme is another. Elon took advantage of misplayed coverages to gain first downs.

“Those types of things, you can preach to ’em and preach to ’em and preach to ’em and then when they see it (happen in a game), they’re all, ‘Geez, that really cost us,’” Roof said.

Defensive linemen have worked on staying in their rush lanes and getting their hands up when the passer is throwing. Linebackers and defensive backs have practiced staying tight on receivers and backs in pass coverage.

“It was all because of mental errors or us missing tackles and things of that nature,” Nealy said.

Duke has converted 17 of 31 third downs in its first two games.

High praise: Coach Paul Johnson said that kicker Harrison Butker's kickoff work against Elon — seven touchbacks on nine kickoffs — is "probably pretty normal for Harrison. That's what we've seen in practice. That's what we saw in high school. We think he's very talented."

Were Butker to continue at that rate — 77.8 percent — he might finish the season as the best kickoff man in the country. Last season, according to cfbstats.com, UCLA led the country in touchback percentage at 76.4 percent.

“If he continues to progress like he has from high school all the way up to whatever, you’ll probably see him kick on Sundays,” Johnson said. “He’s got that kind of ability.”

Injury report: Cornerback Jemea Thomas was in a red jersey Tuesday, meaning he was held out of practice. Johnson did not mention Thomas during his news conference before practice, when he brought up the status of other injured players. Thomas is one of the Jackets' top playmakers on defense. He would be replaced by D.J. White.

A-back Deon Hill will not play because of an illness. Johnson said Monday that Hill was questionable before downgrading him Tuesday. B.J. Bostic will probably start in his place.