The Detroit Lions took to the practice field once again to continue preparing for the Minnesota Vikings.

Dan Skipper, Frank Ragnow and Kevin Zeitler were back at practice, with Ragnow and Zeitler missing Wednesday for rest purposes. Meanwhile, Carlton Davis remained out while dealing with a quad injury.

Initially, coach Dan Campbell expressed optimism about Davis' chances to play against the Vikings. However, Thursday marked the second consecutive practice he's missed.

Davis left Sunday's game against the Dallas Cowboys and entered concussion protocol. While he did not return to the game, he was cleared to return and could've if the game was not already locked away by virtue of a 47-9 final score.

The veteran was acquired by the Lions in a trade during the offseason and has been a key part of their success defensively. He has 30 tackles and a fumbled recovered through the season's first five games.

Defensive coordinator Aaron Glenn praised the work done by Davis' counterpart, Terrion Arnold, along with defensive end Alim McNeill in the win over Dallas.

"We had two guys that played their butts off this game, and that was T.A. and Mac," Glenn said. "You guys can go back and watch and see how they played. They battled their butts off."

On Thursday, it was another chance for the team to indoctrinate new defensive end Isaiah Thomas into the fold. While it remains unclear exactly what his role will be heading into Week 7 and beyond, Thomas has intriguing measurables and physicality.

Glenn explained that Thomas has an opportunity to earn a role beginning this week by competing against the Lions' talented offensive line on the practice field.

This article was originally published on www.si.com/nfl/lions/ as Carlton Davis Misses Thursday Practice.