The Summit County Sheriff's Office said Eaton was found unconscious lying in the road at about 8:30 p.m. Friday after apparently crashing his bike in Summit County, Utah. According to authorities, he was transported to a local hospital, where he later died.
Police said there was "no reason to believe a vehicle was involved in the incident."
"The Utah Jazz are profoundly saddened at the unexpected passing of Mark Eaton, who was an enduring figure in our franchise history and had a significant impact in the community after his basketball career," the team said in a statement Saturday.
"... His presence continued around the organization as a friend and ambassador while giving back as a businessman and volunteer to his adopted hometown in Utah. We extend our deepest condolences to his wife Teri and their extended family. Mark will be greatly missed by all of us with the Jazz."
The 7-foot-4 center spent his entire 11-year career with the Jazz. He led the league in blocks per game four times, and his average of 5.6 rejections per contest in the 1984-85 campaign remains the highest average since the NBA started officially tracking that statistic.
Eaton's career blocks average of 3.51 per game is the best in league history.
The Jazz selected Eaton in the fourth round of the 1982 draft out of UCLA. He was an All-Star selection in 1989 and a five-time All-Defensive Team selection -- three first-team nods and two second-team picks.
"The NBA mourns the passing of Mark Eaton, a Utah Jazz legend and former president of the Retired Players Association," the NBA said in a news release Saturday. "Mark was an All-Star, two-time Defensive Player of the Year and beloved member of our league. We send our heartfelt condolences to his family and many friends."
Eaton's No. 53 was one of the first jerseys retired by the Jazz. In recent years, he served as a mentor to current Jazz center Rudy Gobert, who is the only other player in franchise history to win the Defensive Player of the Year award.
"To my great mentor and friend [Mark Eaton], one of [a] kind and an amazing human being," Gobert posted Saturday on Twitter. "I'm grateful for your presence in my life over the years. Gonna miss our conversations. But I know you'll be watching."
Eaton, who was born Jan. 24, 1957, in Inglewood, Calif., retired from basketball in 1993 and went on to become a restaurant owner, author and motivational speaker.