Mike Ridley set the tone for the Washington Capitals' aggressive play in the victory over Toronto Friday with a resounding first-shift check on Russ Courtnall, the Maple Leafs' leading scorer.

Someone else must set the tone this afternoon, when the St. Louis Blues visit Capital Centre. If Ridley's hit took Courtnall out of the game in a figurative sense, a second-period check of considerably less impact by Rick Lanz removed Ridley from the contest in a literal sense.

Ridley apparently suffered ligament damage to the right knee and, the way he was hobbling around yesterday, he will not be returning to action for a few weeks.

Ridley, the Capitals' No. 3 goal scorer with 13, at least was relieved to learn X-rays revealed nothing serious. A final diagnosis will be made today, when the swelling has subsided.

Of the play that left him limping, Ridley said, "I saw that Kelly {Miller} was setting a pick and I saw him {Lanz} coming. I thought if I cut back quick, he'd go by me. Instead, he just caught my thigh.

"When I fell down, I thought it was just a charley horse. But then I skated and walked off and I felt the knee. I couldn't bend it in and that's what's bothering me now."

Ridley had missed only two games, both because of the flu, since entering the NHL in October 1985. Like the team, he had good and bad stretches this fall, but like his teammates, he played superbly in the first period Friday.

"The whole team played really well," Ridley said. "I was taking the body more and playing more physical. Hopefully, this will get better and I can play the same way."

Right wing Ed Kastelic, who sat out Friday's game, will replace Ridley numerically today. That will require some juggling of lines and Dave Christian, who had two goals Friday, most likely will shift from right wing to center.

Kastelic, scoreless in 20 games, was among a group of players criticized by Coach Bryan Murray earlier in the week for lack of involvement physically.

"You don't like to watch, but you can learn some things," Kastelic said. "We got some good hits and we finished our checks. I've got to do that tomorrow. I would like to get a point, too."

Murray said someone might be summoned from the farm system before the Capitals leave on a trip to Quebec Tuesday and Montreal Wednesday. The most likely prospect is Binghamton center Mike Richard, who equaled the American Hockey League record of a point in 28 consecutive games Friday and was attempting to break it last night against Rochester.

A mixup in ice time at Mount Vernon reduced the Capitals' practice to one hour yesterday. Afterward, the players met one more time and watched videotape of the Toronto game.

"A lot of good things happened last night and I wanted them to see that," Murray said. "But I think we've had enough meetings. We can't have four-hour meetings every day before a game."

Owner Abe Pollin and team president Dick Patrick visited the dressing room before Friday's game and gave the players a vote of confidence.

Then, Murray started the fourth line of Greg Adams, Craig Laughlin and Lou Franceschetti, because, "I wanted to give a message to our other players and a message to them. If they played aggressively and hard, they'd get more ice time, and they did. Greg Adams' role early was very important. Bumping in pursuit of the puck is a very important part of any hockey game."

Asked whether he had any further motivational plans for today, Murray said, "I hope there's no need. We have to work hard and, from a physical point of view, we can all do something. I don't expect everybody to knock guys through the glass, but everybody can pursue and force the defense. We want to play a pressure game and we need everybody working."

In the past, there was little concern when the Capitals stumbled through stretches of the season, because New Jersey and Pittsburgh were so inept a playoff berth was virtually guaranteed. The Devils and Penguins have improved, in large part because of high draft choices, and now there is a genuine six-team Patrick Division race.

"For five years now we've gone through this," Murray said. "It's not pleasant, it's not fun and I don't enjoy the catcalls from the stands. But I believe in this team and I'm sure it will get better.

"This is going to be a very difficult division, with six teams in contention through most of the schedule. As bad as we've played, we're still right there. If we were .500 today, we'd be tied for second."

The players know that a 4-2 victory at home over a sub-.500 Toronto team is no guarantee things have turned around.

"We played well, but we can play better," said defenseman Scott Stevens, the Capitals' leading scorer. "We had some bad moments and a lot of good moments. We can build on it and possibly put a string together."