On August 2, 2005, in the summer following the lockout, the Oilers traded Brewer, Jeff Woywitka and Doug Lynch to the St. Louis Blues for Chris Pronger. At the time of the trade, Brewer was a restricted free-agent, so on August 15, 2005, Brewer accepted the Blues' qualifying offer, signing a one-year, $2-million contract. Brewer's first season with the Blues was a particularly bad one, playing only 32 games as a result of a dislocated left shoulder. Despite this, the Blues re-signed Brewer to a one-year, $2.014-million contract. The 2006-07 season was a bit of a turnaround for Brewer, as he started to play much better under new coach Andy Murray. Amid speculation that he was going to be traded (as he would have been an unrestricted free agent following the season), he signed a four-year, $17-million contract extension with the Blues on February 24, 2007.