Frank Bush replaces Richard Smith as Texans promoted him to defensive coordinator on Tuesday.
Bush had served the last two seasons as a senior defensive assistant for Houston.
Bush, 46, has 18 years of NFL coaching experience, the majority of which came as a LB coach for the Oilers, Broncos and Cardinals. He joined Coach Gary Kubiak in 2007 after serving three seasons as linebackers coach in Arizona. Before that, Bush spent nine seasons in Denver, when Kubiak was the offensive co-coordinator there.
The Texans won five of their last six games in 2008, allowing only 18 points per game in that span. They held Tennessee to 281 total yards in a 13-12 win Dec. 14, and allowed only 294 yards against Chicago in the season finale, knocking the Bears out of playoff contention.
The Texans ranked 22nd in total defense last season. They were 23rd vs. the run and 17th vs. the pass.
The 2009 campaign will be Bush's 25th NFL season as a player, scout and coach.