Nixon was released by the Colts two days earlier after spending the last two seasons with the team.
The Redskins signed Nixon as an undrafted free agent in 2013, but he didn't make the team's regular season roster. The Colts signed him off the Redskins' practice squad in September of that year.
Jackson played in 13 games in 2014 and registered 10 tackles and one sack. He was recently arrested for careless driving and DUI.
Nixon appeared in four games during the 2014 season, starting one. He missed the AFC Championship Game after missing the team's flight.
It is the second straight week Richardson will be inactive.
The Colts are currently 7-point underdogs against the Patriots Sunday.
Nixon played 99 snaps on offense during the regular season, per Pro Football Focus, including all 65 offensive snaps in his team's Week 16 blowout loss to the Cowboys. The tackle was charged with surrendering one sack and three quarterback hurries in Week 16.
Indianapolis is a 6 1/2-point underdog against New England Sunday.
Men's New Era Gray/Burgundy Washington Redskins 2015 NFL Draft 39THIRTY Flex Hat Shop Now!