Could be time to move on for some Bears

It's realistic to expect the Bears will improve their talent level through the draft and with free-agent signings when the market opens at 3 p.m. on March 10.

But it's debatable whether re-signing any of their own 17 unrestricted free agents would make a difference next season, as new general manager Ryan Pace and coach John Fox go about revamping a 5-11 team.

Of those Bears scheduled to become unrestricted free agents next week, none are considered indispensable, even though two of them - cornerback Charles Tillman and linebacker Lance Briggs - have been cornerstones of the defense for more than a decade since they were drafted in 2003.

Of the Bears' other free agents, defensive tackle Stephen Paea is clearly the most valuable based on last year's production, and he's just 26.

Briggs and Tillman both are 34. If healthy, they could help the Bears as they transition to a 3-4 defensive scheme under new coordinator Vic Fangio. But that's a huge "if."

Neither Tillman nor Briggs can expect anything more than a modest one-year offer from the Bears, with incentives based on playing time.

"We've talked to those guys," general manager Ryan Pace said at the NFL Scouting Combine. "It's a slow process. But we recognize (that they're) great Chicago Bears, and that's going to be a big decision for us."

The hope is Pace will handle this situation better than his predecessor, Phil Emery, who bungled a similar situation with Brian Urlacher at the end of the future Hall of Famer's brilliant career.

Briggs has played in just 17 games over the last two seasons because of injuries. He finished last season on injured reserve after suffering a groin injury in Week 11, and he missed three games earlier in the season with a rib injury.

In 2013, Briggs missed seven games with a fractured shoulder, and he was not the same player when he returned for the final two games as he had been during seven straight Pro Bowl seasons (2005-11).

Injuries have cost Tillman even more playing time than Briggs. Tillman missed the final 14 games last season with a torn right triceps, the same injury that forced him to miss the final seven games in 2013.

Paea, a second-round pick in 2011, is coming off a career-best season. He started all 16 games in 2014 at nose tackle and finished third on the team with 6 sacks, doubling his career total. He also was credited with 32 solo tackles, doubling his previous best in 2012, when he started 14 games.

At 6-feet-1 and 300 pounds, Paea is undersized for a nose tackle in a 3-4 defense. But the Bears have no one on the roster who fits the mold of the massive, blocker-absorbing 3-4 nose tackle.

Jeremiah Ratliff (6-4, 303) excelled at nose tackle with the Dallas Cowboys, making four straight Pro Bowls from 2008-11. But Ratliff will be 34 before the season begins, and he has started 21 games in three seasons because of injuries.

Last year's second-round pick, 6-2, 315-pound Ego Ferguson, also is in the mix.

"There's a couple guys who can do it," Pace said. "One of them has done it before in Dallas. It doesn't have to be this big, 350-pound space-eater. You can use him in a variety of ways."

But Paea might be more valuable to a team that plays a 4-3 defense than he would be in the Bears' 3-4 alignment.

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Bears' unrestricted free agents

Bob LeGere's assessment of other unrestricted free agents who played for the Bears last year:

Offensive lineman Eben Britton: Experienced, versatile backup who is just 27 and played frequently as a sixth OL and started four games in 2013.

Center-guard Brian de la Puente: Also has versatility. Started games at center and guard last year but ended season on I.R. (ankle). Turns 30 before camp begins.

Quarterback Jimmy Clausen: Was efficient if not impressive running the offense in only start last year, his first in four years.

Linebacker Darryl Sharpton: Impressive in two starts last season but, as usual, couldn't stay healthy. Undersized, but only 27.

Linebacker D.J. Williams: Physical inside thumper limited to 25 games in previous three seasons because of injuries and will be 33 before camp begins.

Cornerback Sherrick McManis: Nice size and has been an effective special teams player but doesn't figure in base defense.

Safety Danny McCray: Didn't do much to upgrade a weak area last season but is valuable as a core special-teams player.

Wide receiver Josh Morgan: Good-size for possession receiver whose production has plummeted in recent years.

Tight end Dante Rosario: Has marginal value on special teams and as receiver in two-TE sets.

Safety Chris Conte: History of concussions and missed tackles offset his athleticism and occasional flash plays.

Long snapper Jeremy Cain: Reliable fill-in will be 35 later this month, so Bears could look to go younger.

Defensive end Trevor Scott: Would not appear to have a role in 3-4 defense other than as a situational pass rusher.

Fullback Montell Owens: At one time was an excellent special teams player.

Kicker Jay Feely: Veteran, late-season fill-in when Robbie Gould was injured (right quadriceps).