MADISON, Wis. (AP) — The bar is set high for the Wisconsin defense.

The roster might turn over, but the fourth-ranked Badgers' D rarely crumbles. Since 2013, Wisconsin is second nationally in both scoring defense (16.1 points) and total defense (282.6 yards).

But to return to that level this year, Wisconsin might need some young or inexperienced players to grow up quickly. So far, coach Paul Chryst likes what he has seen in the preseason.

The first test for the team's unusual defensive blend of top-flight talent up the middle and untested replacements on the edges comes Friday night against Western Kentucky in the season opener.

"I like what the guys have done. There's a group that's played a lot of football on defense that we have an idea of what to expect," Chryst said after practice on Sunday. "And then we'll have a number of players where this will be their first snaps.

"I feel like they're confident and ready for that next challenge, but it is a challenge," he added.

Wisconsin will rely on a playmaking core up the middle for veteran stability, starting with preseason All-American inside linebacker T.J. Edwards. A key cog since his freshman year, Edwards has more starts (39) than anyone else on defense.

Returning to top-10 status on defense might take a little time as guys get used to each other in game action, but Edwards said he is excited by the possibilities.

"We definitely set our goals high and we want to be around (being a top-flight defense). But I think it comes with chemistry," he said. "With having a lot of new pieces, it's something that we're going to have to build during the games and kind of figure out how everyone plays."

Wisconsin is breaking in new starters at defensive end, outside linebacker and cornerback. At safety, promising redshirt freshman Scott Nelson takes over a starting job alongside four-year starter D'Cota Dixon. Even quarterback Alex Hornibrook has noticed how well Nelson has played in camp.

"Scott's a playmaker. He's an opportunist," Dixon said. "He's much ahead of the game for his age."

He'll begin his college career as a starter, as will another redshirt freshman, cornerback Faion Hicks. Sophomore Caesar Williams, who played two games last season, was listed as the other starter on the season's first depth chart.

"If you don't have a huge natural separation, I think one thing that can separate is consistency, and I think that's what you see in them, the consistent approach," Chryst said.

Outside linebacker might have the smoothest transition with Andrew Van Ginkel and Zack Baun taking over as the starters. Both players have seen snaps as backups, and Van Ginkel showed his playmaking prowess late last season with a combined two interceptions and a fumble recovery against Ohio State and Miami.

Senior nose tackle Olive Sagapolu, who regularly draws double teams, will anchor a line that will have redshirt freshmen Matt Henningsen and Kayden Lyles starting at end because of injuries to presumed starters Garrett Rand and Isaiahh Loudermilk.

Rand is out for the year, while Loudermilk could be back for Big Ten play. Lyles was moved over from offensive line when camp started to help with depth.

It's a work in progress, though the Badgers do have the luxury of a manageable nonconference schedule before the conference opener on Sept. 22 at Iowa.

They also have a rock at inside linebacker in Edwards, who can help raise the level of play of his young teammates.

"I think I can try to be a better leader vocally, but in terms of doing things outside my game, I'm not worried about it at all," Edwards said. "I know those guys are going to make those plays when the time comes."

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