The 23-year-old forward, who was a restricted free agent, had six points (two goals, four assists) in 32 regular-season games with the Blues last season and one goal in 10 Stanley Cup Playoff games to help St. Louis win the first NHL championship in its 51-season history.
Fabbri missed the 2017-18 season after injuring his surgically repaired left knee. Selected by St. Louis in the first round (No. 21) of the 2014 NHL Draft, Fabbri has 72 points (31 goals, 41 assists) in 155 regular-season games and 16 points (five goals, 11 assists) in 30 playoff games for the Blues.