SPARTANBURG, S.C. – The Panthers' defense got competitive about who brought down the first interception of training camp when Keith Taylor Jr. did it on the first day.

On the third day of camp, the offense tallied one of its first big plays at Wofford when Terrace Marshall Jr.. brought in a deep pass from Sam Darnold during a 7-on-7 period.

Head coach Matt Rhule said he was glad to see Marshall, a second-round selection of the Panthers' 2021 draft, demonstrating what he's learned.

"To me, this is all about execution," Rhule said. "Are guys doing things right in full speed? Then execution leads to production. I loved seeing 'Moo' make a play."

Rhule also said Marshall had been held back a bit in training camp due to his high number of reps during OTAs, when he flashed his explosive ability downfield in highlight-worthy moments.

"We kind of dialed his reps down," Rhule said. "He's been playing so hard, his reps were high, and his GPS was high. It's great that he made a play as a result."

Marshall was partially hampered by injuries in his rookie season, finishing his first year with 17 receptions for 138 yards. He appeared in 13 games and started three, though most of his production – including his longest catch, a 23-yarder in Week 3 – came at the front end of last season.

If pulling down the longest completion since the start of camp is any indication, Marshall is still playing hard and looking to make a splash.

– Christian McCaffrey had his first rest day of training camp Friday, part of the preseason plan put in place for the Panthers' star running back.

Rhule said they decided not to have McCaffrey at full speed four days in a row, and that he'll be back participating tomorrow.

"One thing about Christian is no matter what we try to do, his GPS numbers are always going to come out at the very top because of the way he plays," Rhule said.

– As a result of McCaffrey's off day, second-year running back Chuba Hubbard and free-agent pickup D'Onta Foreman had eyes on them, with the opportunity to show their own improvement in camp.

"I think D'Onta had a great spring," Rhule said. "He looks the same now. He does a great job of getting downhill, being that physical runner.

"Chuba, the same thing. In the last year, his body balance and contact balance has really improved. His special teams value is high, so we'll use all three guys."

— Darnold and Baker Mayfield alternated work with the starters during Friday's practice, after each of them spent an entire day with the ones the first two days.

Rhule said that would likely be the case, as they work both into the mix while they compete.

– Both quarterbacks put points on the board in a two-minute segment to end the practice.

Darnold, working with the starters, got the offense into the end zone, with Shi Smith making an impressive-looking (but disputed, though Rhule said it was ruled a touchdown) grab in traffic for the score. After the defense was flagged for a penalty for kicking the ball in frustration, they lined up for a two-point conversion, with Foreman pushing it in.

When Mayfield got his shot with the second offense, he moved them into position for a long field goal, though there were a few stumbles (literally). He bobbled one snap and had to scramble to get out of bounds, but completed a few nice balls and was able to spike to stop the clock for Zane Gonzalez.

Rhule said that while practice is generally scripted, offensive coordinator Ben McAdoo was calling the plays during that end-of-half segment.

— Former defensive coordinator Mike Trgovac was in the crowd for practice, and spent a few moments catching up with one of his best players, assistant general manager Dan Morgan. Trgovac's daughter Jordan now works as part of the Panthers' scouting staff.

— The Panthers worked out some cornerbacks after practice, as they consider adding depth there with Jaycee Horn on PUP and the retirement of veteran Rashaan Melvin.