The week after first practising with St. Louis, 42-year-old Martin Brodeur has been named to start in goal for the Blues on the road Thursday against the Nashville Predators.
Blues head coach Ken Hitchcock made the announcement to the media on Wednesday night.
Brodeur, a four-time Vezina Trophy winner as the NHL's top goaltender, played 21 seasons with the New Jersey Devils, becoming the league's all-time leader in wins (688), shutouts (124) and games played in goal (1,259).
He was not re-signed by the Devils after appearing in 39 games last season with a 2.51 goals against average and .901 save percentage.
Brodeur practised with the Blues on Nov. 27, and earlier this week signed a one-year contract worth $700,000 US plus bonuses for points the team earns while he's in goal.
The Blues are off to a 16-7-2 start but lost starting goaltender Brian Elliott to a lower-body injury last week.
Jake Allen, who defeated Minnesota in a shootout on Saturday, was in goal for the Blues on Wednesday night in a 4-1 loss at Chicago.