Running back Jim Kiick, a key figure in the Miami Dolphins dynasty of the 1970s who helped the team complete the only perfect NFL season in 1972, has died at the age of 73. The Dolphins announced Kiick's death on Saturday, days after his daughter Allie shared on social media that her father's health was declining rapidly. Kiick had been battling dementia and was living in an assisted-living facility in South Florida, where his daughter said he'd been unable to have visitors because of COVID-19 concerns. Along with Hall of Fame fullback Larry Csonka and fellow running back Mercury Morris, Kiick was part of the greatest backfield in Dolphins history. They helped the Dolphins go unbeaten to the Super Bowl crown in 1972 and win a second straight title the following season. Kiick was drafted by the Dolphins in 1968 and played 10 seasons of professional football. The first seven came with the Dolphins, including two in the former American Football League. He earned all-star honors his first two seasons, leading the AFL with nine rushing touchdowns in 1969. He topped 1,000 yards from scrimmage in each of his first four seasons, emerging as one of the league's top receiving threats out of the backfield. bb/acb