St-Denis, 28, spent last season with the Blue Jackets' American Hockey League affiliate in Springfield, where he scored nine goals and 26 points in 60 games. The Quebec native started his NHL career with the Montreal Canadiens organization in 2008-09 before signing with Columbus as a free agent in 2013.
In 17 games with Montreal during the 2011-12 season, St-Denis scored one goal and three points with 10 penalty minutes and a plus-3 rating.
This is a great day for me. This is something I've been thinking about for a long time. This is a great opportunity that the St. Louis Blues organization, (owner) Tom Stillman and Doug Armstrong are giving me and trusting me in doing...This is going to be a great challenge for me.
— Martin Brodeur, after announcing his retirement as an NHL player and becoming a senior adviser with the Blues on Thursday