According to NFL.com's Ian Rapoport, Johnson showed up at the team's facility earlier this week and took his physical.
He is expected to start practicing Saturday morning.
Johnson skipped the Texans' offseason workouts and reportedly requested a trade after saying that he wasn't sure if he would suit up this season.
Houston went 2-14 last season and Johnson did not want to be part of a rebuilding project. Johnson, 33, is under contract through the 2017 season and will make $10 million in base salary this season.
Johnson caught 109 passes for 1,407 yards and five touchdowns last season.