In a statement posted on the team website Tuesday, Sporting KC chief executive Robb Heineman accused Livestrong of "utilizing aggressive tactics designed to force us into an unsatisfactory arrangement." He said the foundation's conduct was particularly surprising considering the organization is "in the midst of a significant transitional phase."
Heineman's statement comes one day after Armstrong admitted in an interview with Oprah Winfrey that he used performance-enhancing drugs during an extraordinary cycling career that included seven straight Tour de France victories. The interview is scheduled to air Thursday night.
"Our faith and trust in this partnership have been permanently damaged; therefore we are terminating our agreement with Livestrong, effectively immediately," Heineman said. "As a result of this decision, our stadium will now be referred to as Sporting Park. While we are ending this relationship, our support of the fight against cancer will endure."
According to ESPN, which was the first to report on the name change, Livestrong recently told Sporting KC it still owed $750,000 of the $1 million promised to the foundation in 2012.
Greg Lee, the chief financial officer for the charity, did not address any details in his emailed statement, but said part of his role is "to ensure that the terms of the foundation's agreements are adhered to.
"If a partner is struggling to meet the terms of an agreement, we do everything possible to reach a fair and reasonable compromise," he said. "If no compromise can be reached, as good stewards of our brand, mission and donors' dollars, we have no choice but to bring that agreement to an end. That is the case here."
Heineman said the $250,000 that the team paid Livestrong for 2012 fulfilled its contractual obligation to the charity.
Armstrong resigned from the board of directors for Livestrong in November, hoping to avoid further damage for the charity in the wake of a report by the U.S. Anti-Doping Agency that accused him of helping run "the most sophisticated, professionalized and successful doping program that sport has ever seen" within his U.S. Postal Service and Discovery Channel teams.
Before this week's interview with Winfrey, Armstrong had long denied doping, and Sporting KC had said as late as last summer that it planned to leave the name of the stadium in place.
Sporting KC announced its partnership with Livestrong in March 2011, and the team's $200 million state-of-the-art soccer stadium opened that June.
The naming rights deal differed from traditional agreements in that Livestrong did not pay to have its name on the stadium. Instead, the club promised to donate $7.5 million in stadium revenues to the organization over six years.
Sporting Park is scheduled to host the MLS All-Star game on July 31.