San Francisco originally signed Jackson on Aug. 8. The 49ers released him Sept. 2 and signed him to the practice squad the following day. He originally was a fifth-round draft pick of the Ravens in 2012.
Jackson has appeared in 22 games, with eight starts, and has made 34 tackles and four pass breakups in his five-year NFL career with the Ravens (2012-15) and Lions (2016).
Reaser was the second of the 49ers’ two fifth-round selections in 2014. From 2014-17, he appeared in 29 games and made 37 tackles, five pass breakups, two forced fumbles and four tackles on special teams.