BOURBONNAIS, Ill. – Lance Briggs and Charles Tillman admit change can be difficult, even when it's necessary.
Like all the Bears in coach Marc Trestman's first camp, Briggs and Tillman are finding they have to adapt. The two most senior Bears on defense in terms of time spent in Chicago are trying to help convert the Bears' cover-2 system that served them so well under former coach Lovie Smith into an equally effective and similar scheme under Trestman and defensive coordinator Mel Tucker.
"I am buying in," Briggs said. "We're all buying in. I'm all in, all in to the program."
If that doesn't happen, there are a handful of players who could be gone next season. The list of those in the final years of their deals include Tillman, cornerback Tim Jennings, defensive tackle Henry Melton, defensive end Corey Wootton and safety Major Wright.
"No one is safe," Tillman said. "I am just here playing football. I've got one year. Do my year and be done. If they want to bring me back, they'll bring me back. If not, go somewhere else. That is kind of the reality of it."
The scheme can make the difference. Tucker kept all the terminology the same, and the team continues to emphasize turnovers.
"It's the same philosophy," Tillman said. "You just don't want to use last year's success, if that makes any sense."
Tillman meant the Tucker version of the cover-2 can't simply count on being as productive as when they gave up 277 points, third best in the league last year, or came within one defensive score of tying the NFL single-season record of 10. They'll have to earn it on the field.
"Last year was a hell of a year," Tillman said. "One of the things, we have to create a new identity once again."
It's an identity without Urlacher, the eight-time Pro Bowl pick who retired after he couldn't reach a deal with the Bears. D.J. Williams is in the middle and James Anderson has replaced Nick Roach on the strong side.
"It's tough," Briggs said. "But we're all grown men. We have to continue to move on."
It's an even greater burden on Briggs because he has volunteered to take on Urlacher's signal calling duties. It's a critical role in any defense, and one usually reserved for a middle linebacker or free safety and not the weak side linebacker. It's the first time he's done it since college.
"I accept it," he said. "I was real comfortable in my role before. Very comfortable. Now I'm getting comfortable with being uncomfortable."
Briggs called getting teammates properly aligned the most taxing aspect of the assignment. And then there is Trestman's practice system. Plays come off every 16 or 17 seconds, so the defense feels like it's almost always in a two-minute drill.
"It's different," Briggs said. "You've been in a system for a long time. You're now told to change and do things a different way. It just takes time."
The defense has more than held its own in early scrimmages against the new-look offense, but was dealt a blow Monday when backup defensive end Turk McBride was ruled out for the season with a torn Achilles tendon.
The Bears are already without defensive end Israel Idonije, who is now with Detroit, and free agent acquisition Sedrick Ellis, who decided to retire at age 28.
Tucker, the former Cleveland and Jacksonville defensive coordinator, expects veterans like Briggs, Tillman and Julius Peppers to lead the way through injuries and whatever other changes are dictated by the new regime
"We want to build on the foundation that's been laid and what's been done," he said.
NOTES: Left tackle Jermon Bushrod missed Monday's practice with a right calf strain that occurred in the warm-up period before practice. Trestman said he's day to day. Jonathan Scott replaced Bushrod at left tackle. ... Wide receiver Brandon Marshall was given Monday's practice off and the entire team will be off on Tuesday. The idea is to give Marshall extra rest as he is coming off hip surgery in the offseason. ... Defensive end Cheta Ozougwu sustained a slight hamstring pull and is day to day.