The defenseman said he made the decision at home after the NHL season was paused March 12 due to concerns surrounding the coronavirus.
"I actually had time to spend soul-searching," Green told The Athletic. "I found that it was time, that I needed to move on. There's a lot of things going on that a lot of people are shielded from, harsh realities in culture, society. Being in quarantine kind of [underscored] that for me. I realized that I've been very fortunate, and a lot of people not so much."
The 34-year-old, who was acquired by the Edmonton Oilers in a trade with the Detroit Red Wings on Feb. 24, played two games with the Oilers before spraining his knee against the Vegas Golden Knights on Feb. 26. He opted out of the NHL Return to Play Plan and did not play in the Stanley Cup Qualifiers, when the No. 5 seed Oilers were defeated in four games by the No. 12 seed Chicago Blackhawks.
"Through this whole thing, it's sort of highlighted some things," Green said. "That hockey was abruptly removed from my life, it was tough for a while. But as the future was more and more uncertain, I became more aware of the things that are now the big things in my life, like my daughter crawling and laughing, teaching my son to fish. These are things you think you're present for, and you think you're around for when you're playing. But your mind as a professional athlete, a lot of times, is thinking about the big stage and performing."
Selected by the Washington Capitals with the No. 29 pick in the 2004 NHL Draft, Green scored 501 points (150 goals, 351 assists) in 880 regular-season games with the Capitals, Red Wings and Oilers, and 37 points (10 goals, 27 assists) in 76 Stanley Cup Playoff games. He scored an NHL career-high 31 goals for Washington in 2008-09 and scored an NHL career-best 76 points (19 goals, 57 assists) with the Capitals the following season.
Green, who scored 11 points (three goals, eight assists) in 50 games for the Red Wings and Oilers this season, was a two-time NHL First Team All-Star (2008-09, 2009-10) and was second in voting for the Norris Trophy, awarded to the best defenseman in the NHL, in each of those seasons.
"Being an athlete isn't the only part of who I am," he said. "I am a husband, father, son, brother, uncle. I've been very fortunate to turn my passion into my profession, but at this point in my life I'm considering other things that I feel called to do."
