EAGAN, Minn. -- Korey Stringer's death from heat stroke in 2001 after he collapsed at practice with the Minnesota Vikings prompted many changes to safety protocols across all levels of sports. About 15 hours after he collapsed, Stringer was pronounced dead, the only known NFL player to die from exertional heat stroke. Casa got connected with Stringer's widow, Kelci Stringer, and agent, Jimmy Gould, through the litigation. "If Korey had gone in a cold immersion tub, we would not be chatting right now," Casa said in a recent interview. The mandatory presence of cold tubs near the practice fields for every team, one of many protocols enhanced in the 25 years since Stringer's death, can be traced to the work that's been done in his honor.