Edmonton Oilers defenseman Mike Green, Vancouver Canucks left wing Sven Baertschi, Dallas Stars defenseman Roman Polak and Boston Bruins defenseman Steven Kampfer will not be rejoining their teams for the NHL's Return to Play initiative.

The NHL season is slated to restart with a 24-team postseason tournament on Aug. 1.

Green, a two-time All-Star, said Saturday that his decision was made due to family concerns.

"Due to the uncertainties surrounding COVID-19 and after much consideration, I've decided for deeply personal family health reasons not to participate in the return to play," Green said in a statement released through the Oilers.

Canucks general manager Jim Benning announced Saturday that Baertschi informed the club of his decision the previous day.

"Sven informed us late yesterday that he has chosen to opt out of the NHL Return to Play Program. It was a difficult decision but ultimately one we respect and understand," Benning said in a statement posted by the club to Twitter.

"We have added Kole Lind to our Return to Play roster and will continue to focus on preparation for camp," the statement continued.

Polak, meanwhile, was not included on the Stars' training camp roster a month after signing a three-year deal with HC Vitkovice Ridera in the Czech Republic that is set to begin next season. At the time he signed the contract, Polak said "I am already determined to stay at home," as opposed to rejoining the Stars for the remainder of this season.

Kampfer said he was opting out due to his family's health.

"This was one of the hardest decisions I've ever had to make," Kampfer said in a statement he released on his Twitter account. "My wife and son have a congenital heart defect which can cause complications with Covid-19. We have taken this very seriously. Family will always be my priority."

The list of players opting out of the NHL's restart is now at five, after the Calgary Flames announced Friday night that defenseman Travis Hamonic is opting out, primarily out of concern for his daughter who has a respiratory illness.

The 34-year-old Green has played in just two games for Edmonton since being acquired from the Detroit Red Wings in late February. Overall, he has 11 points (three goals, eight assists) in 50 games this season.

In 15 NHL seasons, Green has 150 goals and 351 assists (501 points) in 880 career games.

Baertschi has two assists while appearing in six games with the Canucks in 2019-20. The 27-year-old Switzerland native recorded 46 points (13 goals, 33 assists) in 43 games this season with the Utica Comets of the American Hockey League.

Baertschi has collected 138 points (66 goals, 72 assists) in 291 career NHL games with the Flames and Canucks. He was the 13th overall pick of the 2011 NHL Draft by Calgary.

Polak, 34, had no goals and four assists with 24 penalty minutes in 41 games with Dallas this season, his second with the Stars. In 14 NHL seasons with St. Louis, Toronto, San Jose and Dallas, Polak has 26 goals, 114 assists and 643 penalty minutes in 806 career games.

Kampfer, 31, had two assists in 10 games for Boston this season during his second stint with the franchise. Overall, he has 13 goals and 21 assists (34 points) in 211 career games with the Bruins (2010-12, 2018-20), Minnesota Wild (2012), Florida Panthers (2014-17) and New York Rangers (2016-18)

After suspending the season because of the COVID-19 pandemic March 12, the NHL will have 24 teams compete in a modified playoff format, with 16 teams competing in a best-of-five play-in round that starts Aug. 1. The other eight teams (the top four in each conference) will play in a three-game round-robin to determine seeding in the following round.

All Eastern Conference games will be played in Toronto and Edmonton will host all Western Conference games.

The Canucks (36-27-6) will face Minnesota Wild (35-27-7) in the play-in round with Game 1 scheduled for Aug. 2. Edmonton (37-25-9) opens a qualifying series against the Chicago Blackhawks (32-30-8) on Aug 1.

Dallas (37-24-8) will face the Vegas Golden Knights (39-24-8) on Aug. 3 in the first round-robin game for both teams. Boston (44-14-12, league-best 100 points) faces the Philadelphia Flyers (41-21-7) on Aug. 2 in a round-robin matchup.