BOURBONNAIS — Khalil Mack last slept in a small apartment only a few weeks ago, when he visited his brother Ledarius’ place just off the Buffalo campus.

The last time the Bears outside linebacker had slept in a dorm, though, was when he was a student at the same school.

Until he checked into his Olivet Nazarene University digs Thursday.

“It reminded me of UB, man,” Mack said after taking his physical the day before the Bears’ first practice. “It’s a wooden bed . . . I might have to get another layer of cushion on there.”

Welcome to training camp.

Mack skipped the Raiders’ last year, embroiled in a contract dispute that was ultimately resolved when the Bears traded for him and made him the highest-paid defender in NFL history. Before then, he, along with the rest of the Raiders, stayed at the Napa Valley Marriott adjacent to the team’s training-camp practice fields.

ONU is not the Napa Valley Marriott.

“Everybody told me, ‘Yeah, you’re gonna love it,’ ” Mack said. “I don’t know if it’s sarcastic or not. But I’m looking forward to it.”

The Bears are one of 10 NFL teams that still go away to camp. In 2013, they agreed to a series of nine one-year deals to keep them on campus through 2022.

It can be drudgery. But there’s no reason to doubt Mack’s sincerity when he says he’s ready to work. The same player spent Super Bowl LIII lifting weights at his home, motivated to improve on the Bears’ first-round playoff exit.

The defeat only strengthened his resolve.

“Ultimately, we’re hungrier than we were last year,” he said. “I’m speaking for myself, as well. I’m way hungrier than I was last year. It definitely wasn’t good enough.”

Grid View Chicago Bears’ linebacker Khalil Mack #52 greets running back Tarik Cohen #29 after arriving for training camp at Olivet Nazarene University in Bourbonnais, Thursday afternoon, July 25, 2019. Ashlee Rezin/Sun-Times

Chicago Bears’ safety Deon Bush #26 arrives for training camp at Olivet Nazarene University in Bourbonnais, Thursday afternoon, July 25, 2019. Ashlee Rezin/Sun-Times

Chicago Bears’ quarterback Mitchell Trubisky #10 speaks to reporters after arriving for training camp at Olivet Nazarene University in Bourbonnais, Thursday afternoon, July 25, 2019. Ashlee Rezin/Sun-Times

Chicago Bears’ running back Tarik Cohen drives a Polaris Slingshot as he arrives for training camp at Olivet Nazarene University in Bourbonnais, Thursday afternoon, July 25, 2019. Ashlee Rezin/Sun-Times

Chicago Bears’ offensive lineman Cody Whitehair #65 (left) chats with tight end Bradley Sowell #85 after arriving for training camp at Olivet Nazarene University in Bourbonnais, Thursday afternoon, July 25, 2019. Ashlee Rezin/Sun-Times

Chicago Bears’ running back Tarik Cohen arrives for training camp at Olivet Nazarene University in Bourbonnais, Thursday afternoon, July 25, 2019. Ashlee Rezin/Sun-Times

Chicago Bears’ running back Tarik Cohen drives a Polaris Slingshot as he arrives for training camp at Olivet Nazarene University in Bourbonnais, Thursday afternoon, July 25, 2019. Ashlee Rezin/Sun-Times

Chicago Bears’ wide receiver Allen Robinson #12 arrives for training camp at Olivet Nazarene University in Bourbonnais, Thursday afternoon, July 25, 2019. Ashlee Rezin/Sun-Times

Chicago Bears’ offensive lineman Kyle Long #75 checks out Tarik Cohen’s Polaris Slingshot after arriving for training camp at Olivet Nazarene University in Bourbonnais, Thursday afternoon, July 25, 2019. Ashlee Rezin/Sun-Times

Chicago Bears’ linebacker Khalil Mack #52 greets running back Tarik Cohen #29 after arriving for training camp at Olivet Nazarene University in Bourbonnais, Thursday afternoon, July 25, 2019. Ashlee Rezin/Sun-Times

Chicago Bears’ linebacker Khalil Mack #52 speaks to reporters after arriving for training camp at Olivet Nazarene University in Bourbonnais, Thursday afternoon, July 25, 2019. Ashlee Rezin/Sun-Times

Chicago Bears’ running back Tarik Cohen #29 takes wide receiver Taylor Gabriel #18 for a ride in his Polaris Slingshot after arriving for training camp at Olivet Nazarene University in Bourbonnais, Thursday afternoon, July 25, 2019. Ashlee Rezin/Sun-Times

Chicago Bears’ running back Tarik Cohen #29 takes wide receiver Taylor Gabriel #18 for a ride in his Polaris Slingshot after arriving for training camp at Olivet Nazarene University in Bourbonnais, Thursday afternoon, July 25, 2019. Ashlee Rezin/Sun-Times

Chicago Bears’ offensive lineman Charles Leno Jr. #72 arrives for training camp at Olivet Nazarene University in Bourbonnais, Thursday afternoon, July 25, 2019. Ashlee Rezin/Sun-Times

Chicago Bears’ running back Tarik Cohen #29 drives a Polaris Slingshot as he arrives for training camp at Olivet Nazarene University in Bourbonnais, Thursday afternoon, July 25, 2019. Ashlee Rezin/Sun-Times

Chicago Bears’ linebacker Khalil Mack #52 speaks to reporters after arriving for training camp at Olivet Nazarene University in Bourbonnais, Thursday afternoon, July 25, 2019. Ashlee Rezin/Sun-Times

Chicago Bears’ linebacker Joel Iyiegbuniwe #45 arrives for training camp at Olivet Nazarene University in Bourbonnais, Thursday afternoon, July 25, 2019. Ashlee Rezin/Sun-Times

Chicago Bears’ linebacker Leonard Floyd #94 arrives for training camp at Olivet Nazarene University in Bourbonnais, Thursday afternoon, July 25, 2019. Ashlee Rezin/Sun-Times

Chicago Bears’ linebacker Leonard Floyd #94 arrives for training camp at Olivet Nazarene University in Bourbonnais, Thursday afternoon, July 25, 2019. Ashlee Rezin/Sun-Times

Chicago Bears’ offensive lineman Kyle Long #75 arrives for training camp at Olivet Nazarene University in Bourbonnais, Thursday afternoon, July 25, 2019. Ashlee Rezin/Sun-Times

Chicago Bears’ tight end Adam Shaheen #87 arrives for training camp at Olivet Nazarene University in Bourbonnais, Thursday afternoon, July 25, 2019. Ashlee Rezin/Sun-Times

Chicago Bears’ wide receiver Marvin Hall #13 arrives for training camp at Olivet Nazarene University in Bourbonnais, Thursday afternoon, July 25, 2019. Ashlee Rezin/Sun-Times

Chicago Bears’ running back Tarik Cohen drives a Polaris Slingshot as he arrives for training camp at Olivet Nazarene University in Bourbonnais, Thursday afternoon, July 25, 2019. Ashlee Rezin/Sun-Times

Chicago Bears’ quarterback Mitchell Trubisky #10 speaks to reporters after arriving for training camp at Olivet Nazarene University in Bourbonnais, Thursday afternoon, July 25, 2019. Ashlee Rezin/Sun-Times

Chicago Bears’ offensive tackle Rashaad Coward #69 arrives for training camp at Olivet Nazarene University in Bourbonnais, Thursday afternoon, July 25, 2019. Ashlee Rezin/Sun-Times

Chicago Bears’ linebacker Leonard Floyd #94 arrives for training camp at Olivet Nazarene University in Bourbonnais, Thursday afternoon, July 25, 2019. Ashlee Rezin/Sun-Times

Chicago Bears’ running back Mike Davis #25 arrives for training camp at Olivet Nazarene University in Bourbonnais, Thursday afternoon, July 25, 2019. Ashlee Rezin/Sun-Times

Chicago Bears’ quarterback Mitchell Trubisky #10 speaks to reporters after arriving for training camp at Olivet Nazarene University in Bourbonnais, Thursday afternoon, July 25, 2019. Ashlee Rezin/Sun-Times

Chicago Bears’ linebacker Roquan Smith #58 arrives for training camp at Olivet Nazarene University in Bourbonnais, Thursday afternoon, July 25, 2019. Ashlee Rezin/Sun-Times

Chicago Bears’ wide receiver Allen Robinson #12 speaks to reporters after arriving for training camp at Olivet Nazarene University in Bourbonnais, Thursday afternoon, July 25, 2019. Ashlee Rezin/Sun-Times

Chicago Bears’ running back Tarik Cohen #29 drives a Polaris Slingshot as he arrives for training camp at Olivet Nazarene University in Bourbonnais, Thursday afternoon, July 25, 2019. Ashlee Rezin/Sun-Times

Chicago Bears’ running back Tarik Cohen #29 arrives for training camp at Olivet Nazarene University in Bourbonnais, Thursday afternoon, July 25, 2019. Ashlee Rezin/Sun-Times

Chicago Bears’ quarterback Mitchell Trubisky #10 speaks to reporters after arriving for training camp at Olivet Nazarene University in Bourbonnais, Thursday afternoon, July 25, 2019. Ashlee Rezin/Sun-Times

Chicago Bears’ wide receiver Taylor Gabriel #18 arrives for training camp at Olivet Nazarene University in Bourbonnais, Thursday afternoon, July 25, 2019. Ashlee Rezin/Sun-Times

Chicago Bears’ defensive end Jonathan Bullard #90 arrives for training camp at Olivet Nazarene University in Bourbonnais, Thursday afternoon, July 25, 2019. Ashlee Rezin/Sun-Times

Chicago Bears’ wide receiver Allen Robinson #12 speaks to reporters after arriving for training camp at Olivet Nazarene University in Bourbonnais, Thursday afternoon, July 25, 2019. Ashlee Rezin/Sun-Times

Chicago Bears’ running back Tarik Cohen arrives for training camp at Olivet Nazarene University in Bourbonnais, Thursday afternoon, July 25, 2019. Ashlee Rezin/Sun-Times

Chicago Bears’ defensive end Akiem Hicks #96 speaks to reporters after arriving for training camp at Olivet Nazarene University in Bourbonnais, Thursday afternoon, July 25, 2019. Ashlee Rezin/Sun-Times

Chicago Bears’ wide receiver Cordarrelle Patterson #84 (left) greets wide receiver Allen Robinson #12 after arriving for training camp at Olivet Nazarene University in Bourbonnais, Thursday afternoon, July 25, 2019. Ashlee Rezin/Sun-Times

Chicago Bears’ wide receiver Tanner Gentry #19 arrives for training camp at Olivet Nazarene University in Bourbonnais, Thursday afternoon, July 25, 2019. Ashlee Rezin/Sun-Times

Chicago Bears’ offensive lineman Kyle Long #75 arrives for training camp at Olivet Nazarene University in Bourbonnais, Thursday afternoon, July 25, 2019. Ashlee Rezin/Sun-Times

Chicago Bears’ cornerback Kevin Toliver II #22 arrives for training camp at Olivet Nazarene University in Bourbonnais, Thursday afternoon, July 25, 2019. Ashlee Rezin/Sun-Times

Chicago Bears’ defensive tackle Nick Williams #97 arrives for training camp at Olivet Nazarene University in Bourbonnais, Thursday afternoon, July 25, 2019. Ashlee Rezin/Sun-Times

Chicago Bears’ defensive end Akiem Hicks #96 speaks to reporters after arriving for training camp at Olivet Nazarene University in Bourbonnais, Thursday afternoon, July 25, 2019. Ashlee Rezin/Sun-Times

To repeat: Mack — who in 2015 became the first player named first-team All-Pro at two positions, in 2016 was named Defensive Player of the Year and last year had the most sacks of any Bear not named Richard Dent — is more jacked up than ever.

“He’s just one of those players that fits perfectly into our culture,” quarterback Mitch Trubisky said. “He makes people around him better. He makes the defense better because he raises everybody’s level of focus, intensity and competitiveness, and he also makes our tackles and our O-linemen better just competing with them in practice.

“We’re just going to have to take care of each other in practice. But I truly believe that competition brings out the best in everybody, and iron sharpens iron. And he’s one of those guys that’s going to push our offense and make sure everybody’s getting better.”

Even though Mack joined the team eight days before the season opener last year, the Bears were impressed by how quickly Mack made an impact on his teammates, on and off the field.

That influence should be greater in camp.

“Being able to see him and how he goes about everything every day, it inspires you as a player to want to continue to get better,” wide receiver Allen Robinson said. “And to kind of want to get that presence around us, as well.”

Last year at this time, Mack watched every team in the league begin its offseason. He worked out alone, waiting for his contract stalemate to end.

“Ultimately, I knew that whatever happened, I was going to hit the ground running,” Mack said. “I’m glad the Bears gave me that opportunity. I’m still trying to make the most of it.”

Even if it means finding a new mattress pad.

“Ultimately, it starts with the offseason, starts with training camp, starts with the camaraderie — the focus, the determination, the will to win,” Mack said. “Those are some of the things you learn throughout this process. Ultimately, man, one game at a time, one week at a time. It’s going to be a long season, but we want to make the most of it.”