Johnson missed last week's game and skipped Wednesday's workout with a sprained right ankle. Williams left midway through Thursday's practice with an injured groin. He was listed as questionable Friday.
Also, Texans linebacker Brian Cushing returns after a four-game drug suspension.
Giants running back Ahmad Bradshaw is active and is slated to start against the Texans. Bradshaw missed Wednesday and Thursday's practices with an ankle injury but he worked on Friday and will play.