Lewis played in every game last season for the Kansas City Chiefs with 15 starts. He had 56 tackles, including three for losses, and an interception.
The 25-year-old Lewis has spent his entire four-year NFL career with the Chiefs after being drafted in the fifth round in 2010.
Lewis has started 50 games, including all 16 in 2011 when he tied a career high with three interceptions.
The move comes at the end of a busy 24 hours for the Texans. who signed quarterback Ryan Fitzpatrick on Thursday night before trading quarterback Matt Schaub to the Oakland Raiders on Friday for a sixth-round pick in this year's draft.
AP NFL website: www.pro32.ap.org