Nelson joins cornerbacks Desmond King and Lonnie Johnson on the roster. King moved outside last season for the first time in his NFL career. Johnson, a 2019 second-round pick, moved back to the position from safety in 2021.
"Our play at the cornerback position last year was not good enough, it's as simple as that," Texans head coach Lovie Smith said Monday. "If we brought somebody back, we have faith in them. We think that they can fit into the mix some kind of way, but that's a position we'll continue to look to improve. We can't play the type of football that we want to play until we get better at the cornerback position, I will say that."
After signing a $3 million contract with the Philadelphia Eagles, Nelson started opposite Darius Slay and appeared in 16 regular-season games. He finished the season with 1 interception, 7 passes defended and 50 tackles.
Playing predominantly in a zone system that was giving to opponents underneath, quarterbacks completed 67% of their passes -- for a QB rating of 108.4 -- when throwing in his direction in 2021, according to Pro Football Reference.
Nelson, who turned 29 in January, spent the previous two seasons with the Pittsburgh Steelers, recording three interceptions over 30 games.
Originally a third-round pick by the Kansas City Chiefs in 2015, Nelson has appeared in 98 of a possible 113 games. He has eight career interceptions and 59 passes defended.
ESPN's Tim McManus and Sarah Barshop contributed to this report.