MIAMI — Jim Kiick, the versatile running back who helped the Dolphins achieve the NFL’s only perfect season in 1972, has died. He was 73.The team announced the death Saturday.Kiick battled memory issues in recent years and lived in an assisted living home.“He is the best dad I could have ever asked for, and will forever be a legend and my hero,” his daughter, professional tennis player Allie Kiick, wrote on Twitter.She had said last week that because of the coronavirus, visitors weren’t allowed in his room.“I miss my dad,” she wrote Thursday on Twitter. “It’s pretty hard when you’re sitting on the outside of the glass and can’t do anything to cheer him up. He’s lost the spark in his eyes as anyone would in this situation.”The former University of Wyoming star was part of a formidable backfield that included his best friend, Pro Football Hall of Fame fullback Larry Csonka. They earned the nicknames Butch and Sundance, inspired by the popular 1969 movie Butch Cassidy and the Sundance Kid .Kiick (“Butch”) made the American Football League All-Star team in his first two seasons, before the AFL and NFL merged, and played for the Dolphins’ back-to-back Super Bowl championship teams in 1972-73. Kiick had two touchdowns for the ’72 Dolphins in the AFC Championship Game in Pittsburgh, and also scored in the Super Bowl 7 victory over Washington that capped their 17-0 season under Pro Football Hall of Fame coach Don Shula.Shula died May 4 at age 90.Kiick and the speedier Mercury Morris split playing time during the 1972 and ’73 seasons, which gave Shula a potent one-two punch at halfback but sometimes led to second-guessing by fans.“Kiick and Mercury Morris both contributed,” Shula said. “Every Monday there was a controversy, but the bottom line wasn’t bad.”The bruising Csonka compounded the challenge for opponents. He and Kiick met at an all-star game the summer they joined the Dolphins, and as running mates they roomed together, partied together and briefly held out together seeking better contracts.When they posed together for a Sports Illustrated cover ahead of the 1972 season, Csonka flashed a middle finger to the camera, making the cover a collector’s item.In 1975, Kiick, Csonka and future Hall of Fame receiver Paul Warfield left the Dolphins for the World Football League. The package was a watershed worth nearly $4 million over three years for the three players, who played for the Memphis Southmen.But the WFL folded, and Kiick returned to the NFL for his final two seasons, playing for Denver and Washington.In 1973, the two published Always on the Run with the help of New York Times sportswriter Dave Anderson, chronicling their intertwined careers from childhood through the 1972 season, when Kiick lost his starting job to Morris.Although Kiick and Morris competed on the field, they had a friendship off the field which stretched through the remainder of Kiick’s life.”Jim and I shared that spot and we made it work,” Morris said in 2018 at a 72nd-birthday celebration for Kiick. “It was such a perfect fit.”Said Kiick: “He and I together were the best running back in football. We were the perfect combination. What he could do, I couldn’t. What I could do, he couldn’t. Together we could do it all.”James Forrest Kiick was born Aug. 9, 1946 in Lincoln Park, N.J. He led Wyoming in rushing three years in a row and was inducted into its athletics Hall of Fame in 1996.Miami drafted Kiick in the fifth round in 1968.He had his best season statistically for Miami’s 1971 team, which lost to the Cowboys in the Super Bowl, when he rushed for 738 yards and averaged 4.6 yards per carry, both career highs.Kiick also was an excellent blocker and a threat as a receiver. He had 233 career receptions for 2,302 yards.Following retirement, Kiick worked as a private investigator for the Broward County public defender’s office. His daughter is professional tennis player Allie Kiick, who has been ranked in the top 150 on the women’s tour. His father, George, played fullback for the Pittsburgh Steelers in 1940 and 1945.