Detroit Lions rookie running back D'Andre Swift didn't practice Thursday due to a concussion, leaving his status for Sunday's game against the Carolina Panthers in doubt considering the NFL's concussion protocol rules.

It's not clear when Swift suffered the concussion. He was not listed on the team's injury report Wednesday and spoke with the media for almost five minutes after practice Wednesday.

Swift was coming off the first start of his career last Sunday against Washington, when he rushed for 81 yards on 16 carries and caught five passes for 68 yards and a touchdown. Swift has rushed 70 times for 331 yards and four touchdowns while catching 31 passes for 275 yards and two touchdowns this season.

He was asked Wednesday what he could potentially do in his second start against the Panthers.

"Keep being consistent. Keep getting better," Swift said. "There's a lot of stuff I can get better at, looking at the tape from last game. Just keep being consistent and keep getting better each week."

The Lions had been working Swift in more and more over the past four games toward taking the team's primary spot in the backfield from veteran Adrian Peterson, who was signed before Week 1, and Kerryon Johnson, who had been the team's starter the past two seasons.

"It's kind of been a process for him. Coming in, he wasn't able to get as many reps as we hoped that he would at the start of training camp with some of the things that he was working through," offensive coordinator Darrell Bevell said. "So, feel like we've got him up to speed. He's in a good spot and then showed up in the game. He did a great job with the run game. We were able to get him involved in the pass game as well.

"As you watched the games prior, I think you can kind of see some of the things that were coming and how we were using him. He stepped up."

Peterson and Johnson will likely get the bulk of the carries if Swift is unable to play Sunday.

Detroit also had star receiver Kenny Golladay sit out practice Thursday after he returned to practice Wednesday for the first time since suffering a hip injury against Indianapolis. Receiver Danny Amendola also missed his second straight practice due to a hip injury.

Quarterback Matthew Stafford, who is dealing with a right thumb injury, practiced on a limited basis, as did receiver Marvin Jones (knee) and tight end T.J. Hockenson (toe).