The 35-year-old Gomez, a 15-year NHL veteran, attended training camp on a professional tryout. He had seven goals and 27 assists in 58 games last season for New Jersey.
St. Louis added forward Scottie Upshall on Monday, also after a tryout.
The Blues placed forward Patrik Berglund on long-term injured reserve. Berglund underwent shoulder surgery in August and will be evaluated in four months.
Introducing the new official NHL App, available for iPhone, iPad and Android smartphones and tablets. A host of new features and improved functionality are available across all platforms, including a redesigned league-wide scoreboard, expanded news coverage, searchable video highlights, individual team experiences* and more. The new NHL App on your tablet also introduces new offerings such as 60fps video, Multitasking** and Picture-in-Picture.
*Available only for smartphones
** Available only for suported iPads