The four-year veteran, who played his entire career with the San Francisco 49ers before going into the free-agent market earlier this month, was rated by ESPN.com as the 25th-best player available in the veteran pool. He was one of only two players from that group who was still available.
Adams, 26, will sign a four-year contract with the Bears, the financial details of which were not immediately available. The two sides began negotiating in earnest late last week.
In acquiring Adams, a starter for most of his career with the 49ers, the Bears add a proven player at a position which has grown perilously thin in the offseason. Star tackle Tommie Harris should return from the hamstring injury that prematurely ended his 2006 season, but beyond that, there isn't much depth or experience.
The team's other veteran starter, Tank Johnson, is currently serving a four-month jail term for firearms possession and there has been widespread speculation he faces league sanctions, most likely a four-game suspension. The Bears lost key backup Alfonso Boone, who signed with Kansas City as a free agent, and top reserve Ian Scott could perhaps leave as well.
Scott has been negotiating with Atlanta Falcons officials, but the Bears in recent days also demonstrated some interest in re-signing him. The addition of Adams may preclude that.
A second-round pick of the 49ers in the 2003 draft, Adams is an undersized but quick tackle, one whose skill-set should make him an excellent fit in the Chicago defensive scheme. With the 49ers intent on completing their transition to a 3-4 defense in 2007, Adams was ill-suited for the plans there. In fact, as San Francisco moved increasingly to a 3-4 last season, Adams saw his playing time reduced.
He started in only five games in 2006 after starting all 16 contests a year earlier.
In four seasons, the former Penn State standout has 144 tackles, six sacks, a forced fumble and seven passes defensed. He has appeared in 58 games and started in 34 of them.
In other news, the Bears also re-signed Pro Bowl guard Ruben Brown to a one-year deal for $2.2 million, according to ESPN.com's John Clayton. With his re-signing and last year's extension given to center Olin Kreutz, the Bears will return five starters to the offensive line next season.
Len Pasquarelli and John Clayton are a senior writers for ESPN.com