Rookies who have not signed contracts by July 15 must then negotiate through the National Football League Players Association, and may have to choose between skipping training camp or playing without a contract, the NFLPA warned yesterday.

The collective bargaining agreement between the players association and the NFL expires at midnight July 15, and the union then becomes the players' exclusive bargaining representative.

"The result is that individual negotiations will cease," NFLPA Executive Director Ed Garvey told a news conference.

But Jack Donlan, executive director of the NFL's Management Council, the league's labor negotiating arm, disputed Garvey's contention that unsigned rookies must stay home or play without a contract. Nothing prevents them from signing the team's last best offer and reporting for training, Donlan said.

"It's unheard of in the labor movement in this country that you can't hire new employes once a collective bargaining agreement has expired," Donlan said.

Donlan agreed that unsigned rookies cannot negotiate directly with teams after July 15 but instead must go through the NFLPA and the Management Council, which are far from agreement on many issues.

The NFLPA estimated that about 40 percent of the rookies, including half of the first-round draft picks, are unsigned.

Only one of the Washington Redskins' draft choices remains unsigned, Vernon Dean, a defensive back from San Diego State who was the team's second pick. General Manager Bobby Beathard is scheduled to return here this weekend to resume negotiations with Dean, and a spokesman said the team hopes to have him signed by July 15.

Veteran free agents who have not signed, Garvey said, also are barred from negotiating with their teams after July 15. They have no obligation to report. Under terms of the current agreement, which remains in force after expiration, they will receive 110 percent of their 1981 salary or the club's last written offer, whichever is greater.

At his news conference, Garvey also announced that the union has filed an unfair labor practice charge against the Management Council, contending it has failed to bargain in good faith by not making a counterproposal to the union's basic demand that players be paid according to a scale, the money for which would come from 55 percent of the NFL's gross income.

Denying the charge, Donlan said management will make a counterproposal when bargaining resumes in New York Tuesday, two days before the contract expires. But chances for a quick settlement are slim.

Garvey said he would like to aim for a settlement by July 30, "since after that date everything's going to be more complicated for both sides." However, Mark Murphy, player representative for the Redskins, said he expects Sept. 12, the stating date for the regular season, to be the more practical deadline.

Garvey said the NFLPA already has the authorization of two-thirds of its members, which it needs to call a strike, and he discounted published statements by several players saying they would not strike over a percentage of gross revenues.

"The vast majority of players say they will strike," Garvey said. "If a few players won't, they can't go out there and play by themselves."