Brown appeared in 30 games over the last two season for the San Diego Chargers. Brown rushed for 157 yards and one touchdown on 45 carries last season in backing up Ryan Mathews.
Powell last played for the Arizona Cardinals in 2012, appearing in 13 games. Powell rushed for 217 yards on 60 carries and caught 19 passes for 132 yards. He was claimed off waivers by the Philadelphia Eagles last offseason but failed his physical and was released.
Following the release of Brown, the Texans have 89 players on their active roster. They will need to clear a roster spot before the two running backs can both be signed.