The 37-year-old forward scored 711 points (206 goals, 505 assists) in 1,035 regular-season games for the Columbus Blue Jackets and Minnesota Wild, including one goal and one assist in seven games this season, his first with Columbus after signing a one-year, $1.5 million contract Oct. 10.
"Kind of what it came down to was I wasn't able to play at the level that I want to play at," Koivu said. "What I feel for myself, if I can't do the job on the ice the way I want to do it, it also impacts me in the room and the things that I trust and I wanted to do year in and year out so far.
"I think just as a whole, every game I had to push to get ready and then I just couldn't get into the rhythm, just didn't feel the way I want to feel as a hockey player and also be able to enjoy the game."
Koivu said he sought feedback from friends and family, including his older brother Saku Koivu, a forward who played 18 seasons in the NHL and retired in 2014, before making his decision. A meeting with Blue Jackets general manager Jarmo Kekalainen and coach John Tortorella on Tuesday morning put his mind at ease.
"They were both very supportive, so that kind of gave me the peace of mind that the decision is right for me," Koivu said. "I'm grateful for the chance that they gave me, and I had an opportunity to come here and experience something new with a great, great team, great teammates. The way they run the organization and everything about it, it's been a great experience."
Koivu played his first 15 seasons for the Wild after he was the No. 6 pick in the 2001 NHL Draft. He became the first to play 1,000 regular-season games for them Dec. 1, 2019, and is their leader in points (709), assists (504) and regular-season games (1,028), and second in goals (205) behind Marian Gaborik (219). Koivu scored 28 points (11 goals, 17 assists) in a Wild-record 59 Stanley Cup Playoff games.
Koivu was Minnesota captain for the past 12 seasons and left as a free agent after scoring 21 points (four goals, 17 assists) in 55 games last season, his fewest since he scored 21 (six goals, 15 assists) in 64 games as a rookie in 2005-06. He pondered retirement when the Wild decided not to re-sign him after last season but said the chance to play for the Blue Jackets reinvigorated him initially.
"I would like to congratulate Mikko Koivu on a tremendous career," Wild GM Bill Guerin said. "No one worked harder than Mikko during his time with the Minnesota Wild. He was a fiery competitor and a fantastic captain both on and off the ice. Mikko is the franchise leader in so many categories, but the impact he made in our community and the connections he made with Wild fans will live on forever. We wish Mikko all the best in his future endeavors and look forward to honoring him in front of all his fans here in the State of Hockey when we are able."
Koivu said his role as depth forward, and that he was a healthy scratch for a 3-2 win against the Carolina Hurricanes on Monday, did not impact his decision to retire. Though Koivu's time with the Blue Jackets was brief, his impact in the locker room resonated with players and coaches.
"He admits, and we knew going in, his game, he's gotten older and it's slowed down a bit and we could see that as we started, but there was still a tremendous amount of value towards the room," Blue Jackets coach John Tortorella said. "But you know what, I have a ton of respect for him as far as going out on his call."
Koivu said he'd love to have the opportunity to see the Minnesota fans again and thank them, which he wasn't able to do last season.
"Minnesota just really became home for me and the way I was always treated there by the fans, the organization, my teammates," he said. "And also Team Finland, the great memories with them. As of right now, I think I will look back on how much I got from the game of hockey, the people involved and things like that. That's something that I really appreciate, and I'm sure looking back in the next couple of weeks and things like that, you start to realize how special it was."
A native of Turku, Finland, Koivu won a silver medal at the 2006 Torino Olympics and a bronze medal at the 2010 Vancouver Olympics. He helped Finland finish second at the 2004 World Cup and played in six IIHF World Championships, including a first-place finish in 2011. He also participated in two IIHF World Junior Championships, helping Finland finish second in 2001 and third in 2002.
Koivu is fifth among Finland-born NHL players in points and assists, and seventh in games and goals.
"It's amazing when you get around people like that, how quality they are, and that's Mikko Koivu," Blue Jackets captain Nick Foligno said. "So his legacy is, I think, cemented in this league as one of the better players, one of the better people, and it's a privilege to play against him and with him and we are just so thrilled for him."
Koivu said he'd like to remain involved in hockey after a break.
"The game of hockey and the people involved, I think it's a great game and something that I've done all my life," he said. "So hopefully there's something that I will find with the game, but I think time will tell with that one, and now I just want to relax a little bit and take some time off and really think about it."
NHL.com staff writers Tom Gulitti and Amalie Benjamin contributed to this report