The No. 8 Cornhuskers made changes at three of the four positions last week, hoping it will help shut down the Badgers' receivers Saturday night.
They include 6-foot-3, 220-pound star Nick Toon, who matched his career high with seven catches for a career-best 155 yards and two touchdowns against South Dakota last week. Jared Abbrederis, at 6-foot-2 and 180, has 15 catches for 233 yards and 6-foot-4, 220-pound tight end Jacob Pedersen has 11 for 175 yards.
"These coaches aren't scared to switch it up," Huskers free safety Austin Cassidy said. "If something's not working, or something's not working as well as they want it to, they're going to be willing to switch it up at any time."
And they did.
The Huskers were 80th in pass efficiency defense after the first three games, giving up 233 yards a game and six touchdown passes. Green was beaten repeatedly, and Evans played extremely soft coverage.
Pelini wants his defensive backs to challenge receivers.
"You put Dennard and Coop and Daimion out there together, that's a pretty physical defensive backfield," he said. "That's what we lack at times is aggression - getting on bodies and getting hands on people."
Cooper, a redshirt freshman, appeared on special teams and as a backup safety in the first three games. His coaches like his size and speed, thought he could be a sound cover man, and moved him to cornerback on Sept. 19.
His initiation in the 38-14 win at Wyoming didn't go smoothly. He had trouble handling the 7,220-foot elevation and got sick to his stomach in the first quarter. He gave up a 48-yard touchdown to Mazi Ogbonna, who beat him on a slant in the second quarter.
"I just wanted to play a perfect game," Cooper said. "I know it's not possible. I just wanted to make the coaches right by putting me out there."
Stafford made three tackles and broke up two passes against the Cowboys.
Pelini said Cooper and Stafford adjusted well, for the most part.
"When the mistakes happened in the game and they were corrected on the sideline, the next time that route combination or run came up, they had made the correction, and that's good to see," Pelini said. "We wouldn't have tried to make those moves and gone so fast with it if those guys didn't have good instincts."
Dennard, the most experienced player in the secondary, played three quarters against Wyoming and made four tackles.
"He came off the field healthy, and I think he is really confident," coach Bo Pelini said. "It was his first time out there and I thought technique-wise he needs to get cleaned up and get back into who he is."
Wisconsin's balanced offense presents a huge challenge.
Montee Ball and James White are averaging 90 and 76 yards a game, respectively, after each went over 900 yards last season. Russell Wilson is second nationally in pass efficiency and is an explosive runner.
"Any time you have a great running game, if you have a quarterback who is as good as he is, they force you to defend the run and put a lot of pressure on your defensive backs," Carl Pelini said. "You need them in run support but at the same time they have to be disciplined in their keys and cover their guys."
Cassidy said the Nebraska defensive backs won't be intimidated after facing receivers such as Justin Blackmon of Oklahoma State and Ryan Broyles of Oklahoma last year. They beat the Cowboys and lost to the Sooners.
"It helps in the secondary because we know what we're capable of," Cassidy said. "That doesn't mean we're going to go out there and shut people down every single play. ... Playing defensive back, you can't be scared or intimidated to go against someone because that's just a recipe for disaster."