PLAINFIELD, N.J., JULY 22 -- If the storied names on the LPGA tour are going to salvage something for themselves this golf season, this would be the week to begin. When the U.S. Women's Open starts Thursday at Plainfield Country Club, the 1-iron wielding Jane Geddes, the elegant swinger Betsy King and comer Jody Rosenthal might put the final stamp on this year as a changing of the guard.

Nancy Lopez has the distractions of children, Pat Bradley has not been herself, and Jan Stephenson still may ache from her car accident. So, as the final major of the season takes place, a year of apparent transition on the women's tour might come to a climax.

Led by Geddes, some experienced, talented players have seized everything they could get their hands on, while the legends have sat idly at times, either by choice like Lopez, or accident like Stephenson. Whether the more famed veterans can keep from being overrun in the Open remains to be seen. But what is clear is that a new contingent is here to stay.

"I think that's the case. I think it's about time," said Geddes, who in addition to leading the 1987 tour in earnings leads it in matter-of-factness. "Not to take away from Nancy or Pat or anybody else. It's just that the players have come of age."

Geddes is the clear-cut favorite to win the Open and defend the title she won last year in Dayton, Ohio. That victory perhaps prevented Bradley from winning a grand slam, and sent Geddes on a tear that is still in progress. She is a five-time winner this year who is coming off a victory in the Boston Five Classic last week, and has earned $346,947. She has won another of the majors this season, the LPGA Championship.

Last week's win restored Geddes to the money lead over King, who has been almost as successful. King has won three times, including the Dinah Shore in the first major of the season. King was runner-up at the LPGA to Geddes, and has collected $328,556.

Chasing King and Geddes are two more who could easily claim the Open. Ayako Okamoto of Japan is another three-time winner this year, who has earned $293,275. Fourth on the money list is Rosenthal, arguably as hot a player as Geddes. Rosenthal won the Du Maurier Classic in Canada two weeks ago for her first major victory, and was last season's rookie of the year.

What is most interesting about this season is that the ambitious new group dominating it cannot exactly be called a young one. Geddes is a 27-year-old who joined the tour in 1983; King is a nine-year veteran who was player of the year in 1984. Only Rosenthal can rightfully be called an ingenue. What seems to have happened is that they bided their time, improving their games and waiting for Bradley and Lopez to relinquish their grip on the game.

"Other players are definitely geting recognition they deserve," Lopez said. "There are so many players now that can win. When I first started you could almost pick the winner every week, you knew who was going to hold up. Now, you can't shoot even par and win. Because someone might shoot 65."

If this is indeed a permanent change, it has been a rapid one. It perhaps began at last year's Open when Geddes survived an 18-hole playoff to win by two strokes over Sally Little. It remained Bradley's season; she won five tournaments, three of them majors, and collected $492,021 to be named player of the year. But she started slowly this season, while Geddes has never looked back.

Geddes is one of the longest hitters on tour, who carries her 1-iron with ease. She also is a nerveless player who saves her best rounds for Sundays.

"I felt like I was confident enough to win," she said. "But I wouldn't have predicted a year ago that I would have won this many tournaments."

If there is a serious threat to Geddes, it is King, who has dogged her steps all year. King has been hampered by a sprained left ankle and is without her usual caddie, Jim Gilmore, who underwent an emergency appendectomy Tuesday. But King is for the most part healthy and is eager to regain the money lead.

"If I could pick five players who can win, I'd certainly make myself one of them," King said. "And Jane. But maybe winning Boston last week works against her, because she's used up her putts, so to speak."

This new rivalry has become almost as exciting as the former one between Lopez and Bradley. The tour eagerly awaited the return of Lopez from the birth of her second child, and followers of the tour wondered if she could regain her form enough to challenge Bradley's dominance. Instead, Lopez has played just 12 weeks in all and earned $85,855, 17th on the money list. And Bradley, although seventh on the money list with $134,452, has not played nearly as well as she would have liked.

Lopez could not be blamed if she is somewhat distracted this week. Monday she was inducted into the LPGA Hall of Fame in a ceremony at Tiffany's in New York. Also, she has not played in three weeks. That makes her a long shot here and she knows it.

But Lopez is hungry for an Open title, one of the few she lacks.

"It would be nice if I could do it," she said. "This would be the perfect week for it . . . I don't think my career is incomplete without it, but it would be a lot more complete if I could win it."

Bradley, the 1981 Open winner, has the consolation of knowing that nothing could have equaled last season.

"I knew before the season started that the only way to better last year was to win all four majors," she said. ". . . The season is not a washout. I'm not playing up to standard. But when your standards are as high as mine, it warrants some frustration."