New York, NY -- (Sports Network) - Gene Upshaw, longtime head of the NFL players union and Pro Football Hall of Famer, has died at the age of 63.

The first NFL Hall of Famer who played exclusively offensive guard, Upshaw was battling pancreatic cancer.

The former Oakland and Los Angeles Raider had served as executive director of the NFL Players Association since 1983, but had come under fire in recent years by both current and former players for his perceived shortcomings in the position.

Upshaw played his college ball at Texas A&I -- now Texas A&M-Kingsville -- where he logged time as a center, tackle, and end. The Raiders drafted him first overall in the first combined NFL-AFL draft 1967, and the 6-foot-5, 255- pounder held down left guard for the next 15 years for the club.