MIAMI — Jim Kiick, the versatile running back who helped the Miami Dolphins achieve the NFL’s only perfect season in 1972, died Saturday at age 73 following a battle with Alzheimer's disease, daughter Allie said.

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.”

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Kiick ("Butch") made the American Football League All-Star team in his first two seasons and played on Miami's back-to-back Super Bowl championship teams in 1972-73. Kiick had two touchdowns for the ’72 Dolphins in the AFC championship game, and also scored in the Super Bowl victory that capped their 17-0 season under Pro Football Hall of Fame coach Don Shula.

Shula died May 4 at age 90.

Kiick lived in an assisted living home in recent years. Allie Kiick said that because of the coronavirus, visitors weren’t being 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.”

In his NFL heyday, Kiick and the speedier Mercury Morris split playing time with the Dolphins during the 1972-73 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.”

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.

In 1975, Kiick, Csonka and future Hall of Famer Paul Warfield left the Dolphins for the WFL. 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.

James Forrest Kiick was born Aug. 9, 1946, in Lincoln Park, New Jersey. He led Wyoming in rushing three years in a row and was inducted into their athletics Hall of Fame in 1996.

Miami Dolphins running back Jim Kiick is seen in a 1973 photo. (Associated Press)

Miami Dolphins running back Jim Kiick is seen in a 1973 photo. (Associated Press)

Miami drafted Kiick in the fifth round in 1968. He became a starter as a rookie and led the AFL in touchdowns rushing in 1969 with nine.

He had his best season statistically for Miami’s 1971 Super Bowl team, when he rushed for 738 yards and averaged 4.6 yards per carry, both career highs.

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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.

“He is the best dad I could have ever asked for, and will forever be a legend and my hero,” Allie Kiick wrote on Twitter after his death. She's professional tennis player who has been ranked in the top 150 on the women’s tour.

Jim Kiick's father, George, played fullback for the Pittsburgh Steelers in 1940 and 1945.