The San Francisco 49ers announced Saturday they have promoted LB Chase Thomas to the active roster from the team's practice squad. In order to make room on the roster, the team has placed LB Chris Borland on the Injured Reserve List.

Thomas (6-3, 242) originally signed with the New Orleans Saints as an undrafted rookie free agent on April 28, 2013. He was waived by the Saints on August 19, 2013, and acquired off of waivers by the Oakland Raiders on August 20, 2013, before being released on August 31, 2013. He was added to the Atlanta Falcons practice squad on September 17, 2013, where he spent the remainder of the season. Thomas signed a Reserve/Future contract with the Green Bay Packers on January 7, 2014, and was later released on May 12, 2014. Thomas then signed a two-year contract with the 49ers on May 27, 2014. He was waived by San Francisco on August 30, and was signed to the team's practice squad a day later. Thomas, who was promoted to the 49ers active roster on November 8, has played in three games this season and registered one special teams tackle. He was released by San Francisco on November 27 and later signed to the team's practice squad on December 1.

A 24-year old native of Marietta, GA, Thomas attended Stanford University, where he played in 53 games and tallied 229 tackles, 50.5 tackles for loss, 27.5 sacks, nine forced fumbles, four fumble recoveries and two interceptions for the Cardinal.

Thomas will wear No. 58.

Borland (5-11, 248) appeared in 14 games this season, including starts in each of the last eight. He registered a team-leading 128 tackles while adding five passes defensed, two interceptions, one sack and one fumble recovery. Borland was named the Pepsi Rookie of the Week twice (Week 10 & 11) and the NFC Defensive Player of the Week once (Week 11). He was also named the NFL Defensive Rookie of the Month for November after becoming the first player in 20 years to register 70 tackles and two interceptions in a single calendar month.