Mercury Morris, running back and kick returner for the undefeated Miami Dolphins Super Bowl team in 1972, has died, according to a family member. He was 77 years old.

The Miami Herald has confirmed Morris’ death by the Dolphins.

“It is with deep sadness that we announce the passing of Eugene ‘Mercury’ Morris, legendary Miami Dolphins running back and valued member of the NFL family, at the age of 77,” his son GhostWridah, a Miami-based musician whose real name was Troy-Jeffery Morris, posted on X. “Known for his electrifying speed and dynamic play, Mercury was a cornerstone of the Dolphins’ historic undefeated season in 1972 and a two-time Super Bowl champion. His talent and passion left an indelible mark on the sport, and his three-time Pro Bowl selection only cemented his place among football’s greats.

“Off the field, Mercury was a dedicated father, a loving brother, a loyal friend and a pillar of the community. His presence extended far beyond football as he touched the lives of many during his time in Miami.”

Morris was selected in the third round out of West Texas A&M and played for the Dolphins from 1969 to 1975. Along with Larry Csonka and Jim Kiick, he helped form what later became known as the “perfect backfield.”

Morris was a three-time Pro Bowler and two-time Super Bowl winner with the Dolphins, including the team’s repeat championship title in 1973.

Morris rushed for exactly 1,000 yards and scored 12 rushing touchdowns during the 1972 regular season, a league-best performance. The Dolphins finished the season 14-0 and won three more postseason games, maintaining the only undefeated season in NFL history.

Csonka also ran for 1,117 yards that year, making Miami the first team ever to have two runners rush for 1,000 yards in the same season.

Morris was traded to the Chargers in 1976 and played one season in San Diego before retiring.

In 1982, the Pittsburgh native was convicted of drug trafficking. The conviction was later dropped, but he spent more than three years in prison as part of a plea deal. He later spoke about his time in prison as a motivational speaker.

Morris leaves behind five children – Geno, Maceo, Tiffany, Troy and Elliott – and three siblings, according to the family statement.