John Williams, an offensive lineman who played 12 seasons in the NFL, died this morning on a walk near his home in Minnesota. He was 64.

The Minneapolis Star-Tribune reports that Williams, who played his college football at Minnesota and returned to football after his playing days and became a dentist and respected community leader in North Minneapolis, had been recovering from a kidney transplant but had seemed to be healthy and doing well. The kidney donor was a longtime friend of Williams who had been a trainer for the 1967 Minnesota Golden Gophers team on which Williams was an All-Big Ten lineman.

Williams was a first-round draft pick of the Baltimore Colts in 1968 and played for them in Super Bowl III and Super Bowl V. He left the Colts after the 1971 season and signed with the Los Angeles Rams, where he played until 1979. His last game was Super Bowl XIV.

After going to dental school during NFL offseasons, Williams opened his dental practice shortly after retiring. He was also a pilot who flew small planes as a hobby and served on the Metropolitan Airports Commission in the Twin Cities, and he was named the Minneapolis Volunteer of the Year in 1992 for his work with prison inmates.

Williams is survived by his wife, Barbara Butts-Williams, who is the dean of the School of Education at Capella University in Minneapolis and was recently appointed to the Minnesota Sports Facilities Authority, which will work on the development of the Vikings’ new stadium in downtown Minneapolis.