The 25-year-old Nixon is a 6-foot-3, 225-pounder in his second season out of BYU. He played in three games for the Oakland Raiders last season as an undrafted rookie free agent and appeared in three games with the Houston Texans this season before being released.
"It's been a long road getting back up here, but it's been good," Nixon said. "It's nice to come here from Houston and get adjusted to everything on the scout team and take a seat back and really try to learn the defense. I was preparing myself that anytime I had to be called up I'd be ready. Unfortunately it was because of an injury with Diggs, but I'm hoping I can contribute any way possible to help this team win these next four games."
The Rams then signed linebacker Maurice Simpkins to their practice squad to fill Nixon's spot. Simpkins, 27, played at Coastal Carolina and appeared in two games with the Green Bay Packers earlier this season.