Center Ryan Walter, the Washington Capitals' No. 1 draft choice, will be examined today for a cartilage tear in his left knee and faces a strong possibility of surgery as the hockey team is preparing to open training camp.

In another development, Greg Carroll, a center and first-round pick in 1976, skated with Capital players at Fort Dupont yesterday and will probably sign a contract tomorrow.

Walter was tossing a lacrosse ball with a younger brother in his New Westminister, British Columbia, backyard 16 days ago when the knee gave out.

A small tear in the cartilage was detected and the knee was immobilized. When Walter attempted to skate here Monday, however, the pain returned. It was decided to schedule an orthoscopic examination today to determine whether surgery is necessary.

Center Guy Charron suffered a similar tear in his right knee while playing tennis just before camp opened a year ago. After a lengthly period of immobilization, Charron was able to play the full 80-game schedule.

"Sometimes the damnedest things happen," said General Manager Max McNab, whose team has seemed damned often enough in the past. "The timing of this is most unfortunate. However, Ryan is a muscular, strong guy and should come out of it all right."

Nothing that Walter needed surgery to repair a severely torn right knee in 1975, McNab said, "Gordie Howe had the cartilage out of both knees by the time he was 22 and it never seemed to bother him."

Carroll was the 15th player chosen in the 1976 NHL amateur draft with a pick acquired in a trade with Atlanta.

He elected to join Cincinnati of the World Hockey Association, then was traded to New England and shuffled back before recently becoming a free agent. A 6-foot, 185-pounder from Medicine Hat, Alberta, Carroll scored 15 goals in each of his two WHA seasons.

McNab will meet with Frank Milne, Carroll's representative tomorrow and said there appeared to be no obstacles to negotiating a contract.

McNab flew to Toronto late yesterday for today's meeting of the owner-player council. McNab also has an important conference scheduled with Bill Watters, Charron's agent. Charron is entering the option year of his contract and wants the big raise he has earned with 74 goals over two seasons.

McNab is still seeking a winger who can score, after failing to land Pittsburgh's Jean Pronovost, traded to Atlanta, although McNab "did pretty heavily" for him.

"I think there could be reasonable player action during these meetings in Toronto," McNab said, but he declined to speculate on whether the Capitals would be involved in the action.