The 25-year-old Stastny is the son of Hall of Famer Peter Stastny. He played in 12 games last year and had one goal and one assist.
"Yan can play many roles within our organization," team president John Davidson said. "He has skill, is great at faceoffs and can kill penalties."
Stastny was an eighth-round pick by the Bruins in the 2002 draft. His father concluded his career with the Blues and they're the second father-son combination to play for the franchise.
Coyotes sign Hale, re-sign Jones
Hale had two assists and 46 penalty minutes in 58 regular-season games last season. He also appeared in six playoff games with the Flames.
The 27-year-old Hale has 11 assists and 175 penalty minutes in 215 career NHL games with New Jersey and Calgary.
The Coyotes also re-signed defenseman Matt Jones to a two-year contract.
The 24-year-old Jones played 45 games for the Coyotes last season and had two assists and 10 penalty minutes.
He was a third-round pick of Phoenix in the 2002 draft and has one goal, 10 assists and 63 penalty minutes in 106 career NHL games -- all with the Coyotes.
Avalanche sign Tjarnqvist, Durno
The 31-year-old Swede played last season in Russia. In 315 NHL games with Atlanta, Minnesota and Edmonton, he has 16 goals and 80 assists.
The Avalanche also signed forward Chris Durno. He spent the last three seasons in the AHL.
Panthers sign four
Fitzpatrick, MacIntyre and Beckford-Tseu signed two-year deals. DeLory signed a three-year entry-level contract.
In his 10 years in the NHL, Fitzpatrick, 33, has played for six teams. Last season, he only played in 19 games for Philadelphia before the Flyers waived him Jan. 1.
Beckford-Tseu, 24, played in 34 games in the American Hockey League last season, going 15-14-2 for Peoria with a .889 save percentage.
DeLory, 19, scored 25 points in 61 games for the Oshawa Generals of the Ontario Hockey League and MacIntyre, 27, had two goals and three assists for the Providence Bruins in the AHL.