In August 2005, following the lockout, the Oilers traded Brewer, Jeff Woywitka and Doug Lynch to the St. Louis Blues in exchange for defenceman 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 poor one. After playing the first 18 games of the season, Brewer separated his shoulder on November 16, 2005, in a 2–0 victory over the Columbus Blue Jackets. Brewer missed ten games before being activated from the injured reserve list, returning to the St. Louis line-up for a game on December 20, 2005, against the Phoenix Coyotes. Less than a month later, in a game on January 13, 2006, against the Atlanta Thrashers, Brewer collided with the Thrashers' centre Karl Stewart, and dislocated his left shoulder, which ended his season. In just 32 games, Brewer finished his season with nine points, including six goals, two shy of his career best of eight set in the 2002–04 season. Despite his limited play, the Blues re-signed Brewer to a one-year, $2.014 million contract for the 2006–07 season.