The 35-year-old, who has played for the Bruins since the 2006-07 season, is an unrestricted free agent.
"Since the end of the season, as I have thought about my future, it has become clear that I need to make a difficult decision for my family and I," Krejci said in a statement. "At this point in my career and life I need to return to the Czech Republic and play in front of my family who sacrificed so much to help me achieve my NHL dreams. I want to play in front of my parents, brother and friends. I want my children to live where I grew up, spend time with so many Czech family members who love them and create lifelong memories."
Krejci scored 44 points (eight goals, 36 assists) in 51 regular-season games for the Bruins last season and nine points (two goals, seven assists) in 11 Stanley Cup Playoff games. He was an alternate captain the past eight seasons.
Selected by Boston in the second round (No. 63) of the 2004 NHL Draft, Krejci is eighth in Bruins history with 730 points (215 goals, 515 assists) in 962 regular-season games. He also is in the top 10 in games played (seventh) and assists (seventh).
Krejci has scored 124 points (42 goals, 82 assists) in the postseason, second in Bruins history behind Ray Bourque (161). He's also second to Bourque in playoff assists, third in playoff games (156) and sixth in playoff goals. He won the Stanley Cup with Boston in 2011.
Krejci played with HC Vagnerplast Klado of the Czech Under-18 league in 2002-03 and HC Rabat Kladno the following season.
He represented the Czech Republic twice at the Olympics. He scored three points in five games at the 2010 Vancouver Olympics when his country finished seventh, and scored three points in five games at the 2014 Sochi Olympics in a sixth-place finish.
"In January of 2007 when I pulled the black and gold sweater on for the first time, I was 20 years old and was almost 4,000 miles away from home," he said. "Since then, you have embraced me as a Bostonian. I have given everything that I have had to you and the Bruins, and over time, Boston has become a second home to me. I met my amazing wife Naomi here, and our two beautiful children call Boston home. This city and your support are so special to me."
Krejci represented his country in the 2004 IIHF Under-18 World Junior Championship, scoring seven points to help the Czech Republic finish third. Krejci played in the 2005 and 2006 IIHF World Junior Championship, finishing third in 2005.
Krejci played in the IIHF World Championship three times (2008, 2012, 2018), scoring seven points (three goals, four assists) in 10 games to help the Czech Republic finish third, and won the Golden Hockey Stick, awarded to the top Czech ice hockey player, in 2013.
"So for now, I want to thank all the Bruins fans for the support they have shown my family and I over the last 14 years. I will forever be thankful," Krejci said.
"This is not goodbye, I will not be a stranger. I will be Bruin forever, I will see you at the TD Garden soon, and I will always bleed Black and Gold."
