"You're not wearing a tie," coach Tom McVie of the Washington Capitals growled at winner Bob Sirois this morning.

Although his right arm was supported by a sling, Sirois responded with a laugh. An X ray had induced an earlier smile, and Sirois was no longer depressed, as he was Saturday night after being slammed into the boards during the final period of the Capitals' 3-3 tie with the New York Islanders.

Sirois could not restrain the tears when a New York doctor's preliminary diagnosis read "fractured collarbone." The X ray uncovered no break, however, and it appears the injury is merely torn ligaments in the right shoulder. That means days off, rather than months.

While the Capitals, flew here for tonight's game with the Bruins, Sirois returned to Washington for additional X rays and treatment. It marked one more unhappy chapter in a season where every ray of light shinning on Sirois has been quickly blotted out by storm clouds.

During the summer, Sirois' conditioning exercises were interrupted by a siege of food poisoning. On the first day at training camp in Dayton, he leaned back while watching teammates run the mile around the arena parking lot and cut his hand on a piece of glass.

On Oct. 2, during an exhibition game in Hershey, Pa., Sirois suffered strained ligaments in his right knee. He did not make his first regular-season appearance until Oct. 29, when he assisted on a key goal in the 2-1 victory at Denver.

Vancouver's Bob Dailey cracked Sirois with his stick on Dec. 7, sandwiching Sirois' left hand against his own lumber. The results were a broken thumb and four more weeks of enforced idleness.

Starting what he called his "third season" on Jan. 4, Sirois regained his timing and began producing the results both he and the Capitals expected. In the seven prior games to Saturday's injury, he had recorded five goals and four assists, joining Gerry Meehan and Bill Riley on a potent NO. 2 line that relieved Guy Charron, Ace Bailey and Hartland Monahan of much of the pressure from opposing checkers.

Sirois' parents, pleased with his success, flew to Boston today to surprise him. When they learned of his injury, they flew right back home to watch his brother play for Sorel in a junior game. It was enough to make a grown man cry.

Defenseman pete Scamurra, his left thigh reinjured while playing at Springfield, returned to Washington with Sirois . . . Defenseman Bob Paradise has also been idle by recurrent injuries to his stomach muscles . . . Charron's two goals Saturday, for a total of 28, not only game him a Washington one-season record, but also marked his personal high. He had 27 last year for Kansas City, 25 in 1973-74 at Detroit . . . Veteran netminder Roger Crozier is in Dayton, working with rookie goaltenders Jim Bedard and Dale Rideout.