The Packers' strategy against Mackey was direct, said Robinson:

"[Coach] Vince Lombardi said, 'If Mackey catches a short pass, I want everyone to rally around him. Don't let the safety try to take him down.'"

At the same time, Mackey's crushing blocks roiled Green Bay's linemen.

"Willie Davis [the Hall of Fame defensive end] would holler, 'Just keep that Mackey off of me,'" Robinson said. "I tried. But I never left Baltimore without dragging the next morning."

A three-time All-NFL selection, Mr. Mackey also played in five Pro Bowls. In a 10-year career (the last with the San Diego Chargers), he caught 331 passes for 5,236 yards.

In 1969, while still playing, he made the NFL's 50th anniversary team as pro football's all-time tight end.

"To be on the field with John was eerie," said center Bill Curry, his roommate with the Colts. "It was like being in the presence of Superman."

Mackey's kryptonite? Bugs.

"He hated them," Curry said. "Once, before practice in Westminster, running back Tom Matte dropped a live cicada down John's pants. He didn't know it until we were in the huddle and everyone heard this whirring noise.

"John looked up, all serious, and said, 'What's that? Is one of them in here with us?' Then he felt the thing in his pants.

"He ripped those pants off, in the middle of the field, with 300 people watching."

At the same time, said Curry, "John had the presence of mind to yell, 'Surround me! Surround me!' to the rest of us."Of course, we all scattered."

Once, at San Francisco's Kezar Stadium, groundskeepers removed the pre-game tarp, revealing thousands of writhing red earthworms.

"John took one look at those things and said, 'They're not going to get on me,'" Curry said.

He caught a half-dozen passes that day but never hit the ground. The 49ers couldn't bring him down. At game's end, his was the only white jersey on the field.

Players' advocate

Despite the accolades, Mr. Mackey was no shoo-in for the Hall of Fame. Most believe his involvement with the NFLPA kept him out of Canton until his 15th and final year of eligibility.

As the union's first president after the merger of the National Football League and the American Football League in 1970, Mr. Mackey quickly aroused the owners' ire. That July, he organized a three-day strike that won the players $11million in pensions and benefits. In 1972, he filed and eventually won a landmark antitrust suit that brought them free agency. (The union bargained it away in 1977.)

"He was the right man at the right time," said Mr. Braase, who preceded Mr. Mackey as head of the players association. "We were a fractured group until John began putting permanence in [the union's] day-to-day operations. He hired administrators and a general counsel.

"He had a vision for that job, which was more than just putting in time and keeping the natives calm. You don't get anything unless you really rattle the cage."

Mr. Mackey's legacy can be found in the multimillion-dollar contracts NFL players enjoy, said Ozzie Newsome, the Ravens general manager.

"All of the benefits of today's players come from the foundation laid by John Mackey," said Mr. Newsome, himself a Hall of Fame tight end. "He took risks. He stepped out. He was willing to be different."

"John Mackey was one of the great leaders in NFL history, on and off the field," NFL Commissioner Roger Goodell said in a statement. "He was a Hall of Fame player who redefined the tight end position. He was a courageous advocate for his fellow NFL players as head of the NFL Players Association. He worked closely with our office on many issues through the years, including serving as the first president of the NFL Youth Football Fund. He never stopped fighting the good fight."

Off the field, Mr. Mackey drove a Bentley. He emceed a concert by the Baltimore Symphony Orchestra. He did a weekly sports report on WJZ-TV and served as sports director of WEBB radio. He starred in a CBS quiz show, "Alumni Fun," as a member of the Syracuse University team. He published an autobiography, "Blazing Trails."

"John was an elegant guy, from his vocabulary to the way he conducted himself in public," Mr. Vogel said. "He enhanced the image of athletes. He raised the bar."

Mr. Mackey is survived by his wife, Sylvia, of Baltimore; a son, John Kevin Mackey, of Atlanta; two daughters, Lisa Mackey Hazel of Bowie and Laura Mackey Nattans of Baltimore; and six grandchildren.

The family will be receiving friends from 6 p.m. to 9 p.m. July 15 at the Burgee-Henss-Seitz Funeral Home, 3631 Falls Road. Plans for an August memorial service are pending.

In lieu of flowers, donations may be made to the Association For Frontotemporal Degeneration, Radnor Station Building 2, Suite 320, 290 King Of Prussia Road, Radnor, Pa. 19087, or to the Sports Legacy Institute, P.O. Box 181225, Boston, Mass. 02118.

Baltimore Sun researcher Paul McCardell contributed to this article.