Even though free agency has been the major reason for the dramatic salary increases in professional basketball and baseball, National Football League players at their annual convention overwhelmingly rejected making it a major demand in their negotiations with the league.

The views of proponents of free agency were overshadowed by support for obtaining a percentage of the NFL's annual gross revenue, a bargaining issue that already has been rejected by the league.

Support for the concept of percentage of the gross was reinforced in today's closing session when the members took another straw vote. This time, only one player, Denver's Keith Bishop, stood in opposition, compared with between seven and 10 Tuesday. Bishop later told the meeting he would support a strike.

The members, in response to another straw vote, unanimously responded in the affirmative to a question by President Gene Upshaw concerning whether they would be willing to strike over percentage of the gross. But Upshaw said this was not a strike authorization vote, which requires approval of two-thirds of the membership.

The players also supported a resolution calling for a rollback in ticket prices, but were undecided about whether that issue would be made part of the union's bargaining demands. Upshaw also sent a telegram to the NFL asking that the league adopt the resolution.

Upshaw also brought up the possibility that the NFLPA could form a new league as a stopgap measure if the players are locked out of training camp this summer by the NFL.

"We've discussed the possibility of a new league," Upshaw said. NFLPA representatives claimed that the organization already has begun formulating details of the league, but they refused to discuss specifics. It is the NFLPA's belief that in case of a lockout, the players would automatically become free agents.

Free agency in baseball and basketball has made millionaires of some athletes and has resulted in lucrative contracts for many average players. Average salaries in both sports are far ahead of pro football's, despite the fact the NFL generates by far the highest revenues of any pro sports organization.

But NFL players have been persuaded by Ed Garvey, the NFL Players Association executive director, and the NFLPA executive board that free agency will never work in the NFL. The NFLPA argues that the owners, because of their large revenues and monopolistic organization, have no incentive to win and that if a new free agency system were implemented, it would fail just as miserably as the one instituted by the 1977 bargaining agreement.

Garvey admits there is sentiment within the league for free agency. But he has surveys and the results of this convention to back up his contention that the players do not rank it as a primary demand.

The NFLPA membership survey asked players to rank in importance what bargaining priorities they hoped the union would achieve. Free agency ranked only fourth, behind higher wages, guaranteed contracts and adding a cost of living factor to the pension.

The same survey, which was answered by 520 of the NFLPA's 1,400 members, showed that 92 percent supported percentage of the gross as the No. 1 priority.

Garvey has attempted to pacify free agency proponents by including it within the percentage of the gross concept. The NFLPA is demanding that after three years, a player will become a free agent without compensation or right of first refusal. But bargaining on that issue will come only after percentage of the gross is obtained, according to NFLPA officials.

The NFLPA maintains that the NFL's enormous success the last decade is also the major reason why percentage of the gross, not free agency, is the only way to tap into the league's riches.

"In baseball and basketball, stadiums aren't sold out for almost every game and they don't have $14 million a year (per franchise) coming in from television (under the new TV contract)," Garvey said. "Pete Rozelle has told Congress that the teams share 95 percent of all revenues equally and that they are one entity without competition off the field. Whether Baltimore wins or loses, it won't make that much difference in Bob Irsay's revenues. He'll wind up making almost as much money as if he went to the Super Bowl.

"In baseball and basketball, owners need to sign superstars to fill up the stadium and make more money. And the better the team, the better the TV contract. But win or lose, the Redskins have RFK sold out and they get their equal TV share.

"So why bid on players? Why cut into profits by increasing salary levels? Where else are the players going to go? It's a closed shop. We don't want any money that will come extra from the fans' pockets. We just want some of what the owners already have."

Garvey has won over players such as Detroit's Stan White, a lawyer and a backer of Reaganomics, and Washington's Mark Murphy, who soon will have a master's degree in economics. Neither could be considered a yes man to the rest of the NFLPA leadership.

Murphy: "I went back to 1976, when there was no compensation if you signed a free agent. There was hardly anyone signed and most of those that were went to the Redskins and George Allen. We are banging our heads against the wall if we try that way again."

White: "I'm a free enterprise person, but it wasn't hard to convince me, because if I was an owner, I wouldn't bid for players because I wouldn't help myself that much. If the owners would say they no longer will share in revenues like they do, I'd say drop percentage of the gross and go for free agency."