Josh Kreutz — wearing his dad’s number — ‘giving it my all’ in tryout. 4 things we learned from Chicago Bears.

“It’s going to come down to how I practice, how I prepare, and hopefully I can show that over these next two days,” Kreutz said.

He said he got a lot of coaching in pro-style habits from Olin, who was both tough on him and encouraging.

“Working a lot (on) wide-zone techniques and backside hand, backside leg, aiming points and really getting the playbook down,” the younger Kreutz said. “Those are the main things right now.”

At least Kreutz has someone who can relate with him: Jai Williams, a 6-5, 230-pound defensive end from Quincy — and the son of former Bears right tackle James “Big Cat” Williams — also received a tryout.

Olin Kreutz played for the Bears from 1998 to 2010 and Big Cat Williams from 1991 to 2002, so the two players — and their families – overlapped for five seasons.

“I’ve known Jai since we were kids,” Josh Kreutz said. “We’ve trained together through this process.”

2. Coaches exposed Dillon Thieneman to a range of concepts.

Thieneman may have waited his whole life until the moment the Bears made him the 25th draft pick, but the weight of it all sunk it during his first practice as a pro.

“I was actually just talking to a guy and I was like, you get kind of nervous before you get out there on the field,” he said. “And then you get out there and you’re like, I’m just playing football again and we’re in the NFL right now, so that’s awesome.”

He already had a rookie hiccup, probably the first of many. He shadowed the wrong man during a three-on-three drill.

“I was supposed to climb as the corner, so I messed up on that one and then we redid it,” he said. “I got it right.”

The Bears had him cross-training at multiple positions. That’s standard operating procedure for all players under coach Ben Johnson’s regime, but it’s particularly important for Thieneman, who’s expected to switch between free and strong safety with free-agent acquisition Coby Bryant, partly to disguise coverages.

“They want me to know both positions, kind of know all the DB positions,” Thieneman said. “But as of right now, I’m playing some strong safety, just still understand what free safety is doing.”

Probably the only stability Thieneman can take comfort in right now is his jersey number: 31. He kept the same number from his two seasons at Purdue — where older brothers Jake and Brennan played as walk-on safeties — to his one season at Oregon and now with the Bears.

“It’s a combination of my brothers’ numbers,” Thieneman said. “In college, (Jake) was 41, (Brennan) was 38, so I just combined them to 31.”

3. Ben Johnson explained the comings — and one notable going — at Halas Hall.

Rookie camp is symbolic of a new NFL cycle. The top prospects have been drafted, the big-name free agents have signed and the Cinderella hopefuls have been invited. Now the players start to touch grass again.

“Man, always exciting to get the rookies in the building,” Johnson said before practice. “We’ve got a lot of energy. The coaching staff is excited to get going, and really, more than anything — I know we’ll hit the grass and we’ll have walk-throughs and all that — but it’s more about just introducing them to our way of life.”

Apparently one player couldn’t make the adjustment to the Bears’ liking. On Thursday they waived cornerback Zah Frazier, a fifth-round draft pick in 2025 out of UTSA.

Frazier missed all of last season for personal reasons, though the Bears didn’t elaborate.

“Zah’s a guy we’ve had here for over a year,” Johnson said. “It’s just one of those things when we’re looking at the roster, where he’s at, where we’re at, it was time to part ways.

“Appreciate everything that he contributed while he was here. It opens up a roster spot and opportunity to make this team.”

Bears brass had expressed optimism earlier about Frazier getting a full offseason and a fresh start. However, Johnson said, “The trajectory was off so we decided to go a different direction.”

4. Sam Roush relishes his role in the Bears offense.

When the former Stanford tight end tries to pick up a new system, he focuses on one aspect first.

“Formations,” Roush said. “I’ve been told when you’re learning a new playbook you want to start with formations, and then you can go into motions and shifts and learn all that.”

Johnson’s complex offense won’t be easy on the rookie, but the Bears drafted Roush — a blocking tight end with receiving prowess — in the third round to add even more punch to the playbook.

Last season the Bears used 13 personnel (one running back with three tight ends) on 94 plays, a rate of 8.5% that was fifth-highest in the NFL, according to Next Gen Stats. The Los Angeles Rams led the league with 331 plays (30.5%) in 13.

Roush, who’s expected to replace Durham Smythe as the third tight end in those formations, believes his playing style will mesh well with Johnson’s playbook.

“It’s a run-first offense and then a lot of the passing game happens off that, play actions and whatnot,” he said. “I pride myself in my ability to run block, and that’s something I’m definitely going to do a lot of. I think I’ll be able to showcase that in the offense.”