The San Francisco 49ers placed linebacker Chris Borland on injured reserve and promoted linebacker Chase Thomas from the practice squad to the active roster Saturday.

Borland, a rookie who is out for the season with an ankle injury, played 14 games this season, including starts in each of the last eight. He had a team-leading 128 tackles with five pass breakups, two interceptions, one sack and one fumble recovery.

Thomas originally signed with the New Orleans Saints as an undrafted rookie free agent out of Stanford in 2013. After stints with the Saints, Oakland Raiders, Atlanta Falcons and Green Bay Packers, he was signed to the 49ers’ practice squad Dec. 1.