“There would be six or eight guys competing for my spot and nobody competing for his,” Beach said, referring to Parrish, who has become one of his closest friends. “That’s where the stacking concept comes from. They would stack black cats behind each other; that was a reality. If you came to the Cleveland Browns and you wanted to play cornerback, there were going to be five brothers over there behind me.”

All 167 cornerbacks listed on active N.F.L. rosters last Monday were African-American, although Julian Edelman, a receiver who is white, has played a few snaps at cornerback for the injury-plagued New England Patriots. The evolution to today’s rosters began with the emergence of the American Football League in 1960. While the N.F.L. maintained quotas and engaged in steering and stacking, the rival A.F.L. was snatching up talented players wherever it could find them, especially at historically black colleges.

“You had more black guys coming into the league who were receivers who could fly, and they had to have defensive backs who could fly with them,” Beach said.

At some point, white players stopped believing they could fly. No more protection from open competition; everyone had to prove himself on a level playing field. Like the success of black fighter pilots, the presence of 64 African-American starting cornerbacks in the N.F.L. is an American triumph of meritocracy over protectionism.

The long-term negative effect of discriminatory practices of the 1950s, ’60s and ’70s is reflected in the almost complete abandonment of cornerback by young white athletes aspiring to play the position at the most competitive high schools. Dallas Jackson, who specializes in high school recruiting for Rivals.com, has seen the consequences.

“I’ve been at Rivals.com for seven years; there has not been a white cornerback who has stood out,” Jackson said “I don’t think we have invited one to our U.S. Army All-American game.”