Placing veteran center Will Montgomery on injured reserve was only the first of several roster moves the Bears made Tuesday.
They also signed safety Sherrod Martin, promoted tackle Nick Becton from the practice squad to the 53-man roster, and waived punter Spencer Lanning and linebacker John Timu.
Martin has appeared in 72 games with 38 starts over six seasons with the Panthers (2009-13) and Jaguars (2014), recording 195 tackles, eight interceptions, 22 pass breakups, four tackles-for-loss, five forced fumbles, one fumble recovery and 19 special-teams tackles.
Martin was selected by the Panthers in the second round of the 2009 draft out of Troy. Last season he appeared in 13 games with two starts for the Jaguars, registering 14 tackles, one interception, two pass breakups, one forced fumble and two special-teams tackles.
Becton spent the first four weeks of the season on the Bears practice squad. He entered the NFL with the Chargers in 2013 as an undrafted free agent from Virginia Tech, appearing in one game as a rookie. Becton spent time with the Giants and Saints last year, but did not play in a game.
Lanning signed with the Bears Saturday to replace injured punter Pat O'Donnell in Sunday's game against the Raiders. Lanning, who spent time with the Bears as an undrafted rookie in 2011, averaged 45.3 yards on three punts and held for Robbie Gould's three field goals without a miss, including a 54-yarder and game-winning 49-yarder.
Timu signed with the Bears in May as an undrafted free agent from Washington. He appeared in the first four games of the season on special teams.
The Bears also made practice squad moves Tuesday, signing center Barrett Jones and defensive tackle Brandon Dunn, waiving defensive tackle Terry Williams, and placing receiver Jalen Saunders on practice squad/injured.
Jones was selected by the Rams in the fourth round of the 2013 draft out of Alabama, where he was part of three national championship teams and won the Outland Trophy as the nation's best interior lineman, the Rimington Trophy as the country's top center and the William V. Campbell Trophy, which is considered the "Academic Heisman."
Injuries limited Jones to 10 games his first two seasons with the Rams. He was waived by St. Louis as part of final cuts this year and spent time on the Steelers practice squad.
Dunn was waived by the Bears on Saturday to make room for Lanning on the roster. Dunn originally signed with the Bears last year as an undrafted free agent from Louisville. He has appeared in four games over two seasons, recording six tackles and one pass breakup.