Chicago Bears left guard Chris Williams was placed on injured reserve after undergoing wrist surgery, head coach Lovie Smith confirmed Monday.

Williams hurt his left wrist in the second quarter of Sunday's victory over the Detroit Lions. He needed emergency surgery that night.

The former first-round pick started all nine games this season for Chicago, which has won four in a row to improve to 6-3.

Chicago also signed defensive end Chauncey Davis to a two-year contract. Davis had 178 tackles, 10 sacks and two interceptions in 96 games (25 starts) over six seasons (2005-10) with the Atlanta Falcons.

The Bears waived defensive end Nick Reed, who appeared in seven games for Chicago this season.