The 30-year-old forward scored 59 points (29 goals, 30 assists) in 69 games with the Florida Panthers last season and five points (three goals, two assists) in four Stanley Cup Playoff games. Hoffman has scored at least 22 goals in each of the past six NHL seasons and has at least 56 points in each of the past five.
A training camp PTO allows the player to participate in all training camp activities but does not create any exclusive rights of negotiation. Hoffman will remain able to sign a contract with any NHL team while the PTO is effective. The PTO expires at the end of training camp.
The Blues will begin training camp Jan. 3.
Selected by the Ottawa Senators in the fifth round (No. 129) of the 2009 NHL Draft, Hoffman has 359 points (172 goals, 187 assists) in 493 regular-season games and 19 points (10 goals, nine assists) in 29 playoff games.