Still wary of possibly losing starting weakside linebacker Warrick Holdman as a restricted free agent, the Chicago Bears on Friday added a terrific insurance policy, with ESPN.com learning the team has reached an agreement with nine-year veteran Mike Caldwell.

	Caldwell

A starter in all 16 games for the Philadelphia Eagles in 2001, Caldwell recorded a career-best 95 tackles and distinguished himself on one of the NFL's premier defensive units. He will sign a four-year contract worth $4.7 million and the deal includes a $750,000 signing bonus and also a workout bonus of $250,000 that he will be paid before training camp begins.

It is a strong acquisition for the Bears, who get an immediate replacement if Holdman departs and a great rotational player if he doesn't.

Holdman is a restricted free agent and Chicago tendered him the low qualifying offer of $563,000 last month. That low number, and the fact a Bears paperwork snafu means he can be signed with no draft choice compensation, had made Holdman an attractive target. The Bears retain a right of first refusal, but Holdman has met with several clubs and the conventional wisdom is that one of them will sign him to an offer sheet.

The Bears would then have seven days to match the offer sheet.

Caldwell, 30, visited with several teams over the first two weeks of free agency and Pittsburgh was also very interested in signing him.

Always a productive defender when he got playing time, but usually relegated to special teams throughout much of his career, Caldwell finally earned a full-time spot in the lineup at weakside linebacker this season and he responded with a standout performance for Eagles coordinator Jim Johnson.

In addition to his 95 tackles, Caldwell registered three sacks, two forced fumbles and also seven passes defensed. For his career, he has played in 134 games and started 46 contests, and has 452 tackles, 11½ sacks, eight interceptions and 45 passes defensed. The final numbers are indicative of his abilities as a "nickel" linebacker, a role he probably will fill with the Bears regardless of whether Holdman departs or not.

The former Middle Tennessee State star entered the league as a third-round choice of Cleveland in the 1993 draft. He played for the Browns (1993-95), Baltimore Ravens (1996) and Arizona Cardinals (1997) before signing with the Eagles as a free agent in 1998.

Len Pasquarelli is a senior writer for ESPN.com.