"Jaromir's career speaks for itself," Flames general manager Brad Treliving said in a news release. "He is a legend in our sport and we are very appreciative that he selected Calgary to pursue his career in the NHL. Regretfully, with a late start to his season combined with nagging injuries, he wasn't in a position to perform at the level both he and our team had hoped.
"During his short time in Calgary, Jaromir demonstrated tremendous leadership and professionalism, especially with our young players. We thank him for his contributions to our group both on and off the ice."
Jagr, 45, signed a one-year deal with the Flames in October. Calgary was his ninth NHL team -- but first in Canada. Injuries plagued Jagr this season; he appeared in 22 games, notching seven points with one goal and six assists.
The Flames put Jagr -- who hasn't played in a game since Dec. 31 -- on injured reserve Sunday with what the team called a lower-body injury.
"Although I am very disappointed that things did not turn out as we had hoped due to a number of circumstances, I am deeply grateful to the Flames, the fans and the City of Calgary for having welcomed me so generously," Jagr said in the Flames' news release. "I now look forward to continuing the season in Kladno."
Jagr is a native of Kladno and owns the team he will play for. Jagr won't make an appearance in the Olympics, as HC Kladno is in the Czech second division, a league that does not break for the Olympics. Jagr will attempt to get the team promoted to Czech Republic's top league, Czech Extraliga.
Jagr is considered one of the greatest hockey players of all time and won two Stanley Cups with the Pittsburgh Penguins, in 1991 and 1992. He is also an Olympic gold medalist and two-time world champion.
He has played in 1,733 games over the course of nearly 24 seasons in the NHL. His 1,921 points are second in NHL history behind Wayne Gretzky (2,857), and his 766 goals are third behind Gretzky (894) and Gordie Howe (801).
The Associated Press contributed to this report.