Jim Langer, the Pro Football Hall of Fame center who was literally in the middle of the Miami Dolphins’ perfect 1972 season, died on Thursday in Coon Rapids, Minn. He was 71.

The cause was a heart-related problem, his wife, Linda, said.

Langer was a first-year starter and played every offensive down for the 1972 Super Bowl champion Dolphins, the only N.F.L. team to go unbeaten and untied in 17 games. The next year he helped the Dolphins repeat as champions and began a stretch of six consecutive Pro Bowl seasons for Miami, during which he played in 128 games in a row.

James John Langer was born on May 16, 1948, in Little Falls, Minn., and grew up about 12 miles south of there in Royalton. He was a standout linebacker and baseball player at South Dakota State but went undrafted. He signed with Cleveland as a rookie in 1970 but was cut. He then joined the Dolphins and made the team as a center in Don Shula’s first season as Miami coach.