It has been fashionable this season to tout the New York Islanders' Bryan Trottier, NHL scoring champion with 134 points, as the league's most valuable player.

Trottier was named player of the year by the Hockey News and seems likely to replace Guy Lafleur as the Hart Trophy (MVP) winner, just as he succeeded the Montreal star as the scoring king.

At least one vote in the Hart balloting, however, will go to Trottier's teammate, defenseman Denis Potvin. Trottier is an outstanding center and a fine all-round player, but Potvin really makes the Islander go.

There is little doubt that Potvin will be named the league's best defenseman for the third time in four years. He is an excellent puck carrier and playmaker, he is a tough body checker, he has a deceptive shot from the point and he exudes confidence to his teammates. It short, he resembles Bobby Orr.

Folk have been saying that since Potvin was 19 years old, playing for the Ottawa 67s, and it is to Potvin's eternal credit that he was able to play so well under the pressure of meeting unreasonable expectations.

"There's Bobby Orr and there's me, Denis Potvin," the Islander says, "and Orr did things I don't do, and I do things he didn't do. You can't compare us. I don't want everybody measuring me against Orr."

Whether Potvin likes it or not, such comparisons are inevitable. This season Potvin became he only defenseman other than Orr to better 100 points in a season, recording 101 although he missed seven games. In his six NHL seasons, Potvin has collected 155 goals and 503 points. In his first six campaigns, Orr's figures were 152 and 512.

"The championship was the big thrill, not the 100 points," Potvin said of the season just ended, when the Islanders edged Montreal for the No. 1 spot overall. "No comparison at all."

He meant it, too. Potvin has always been forthright, telling things the way they are, not the way they would look best in the newspaper. For example, he did not hide behind false modesty when asked if he thought he was the league's best defenseman.

"Yes, I think I am the best defenseman in the NHL," Potvin said. "Thanks to (Coach) Al (Arbour), I have learned to play defense the right way while still retaining my value as an offensive defenseman. That's the way I play best and it's the way the club feel I'm most effective. I don't worry about points anymore."

Although Potvin is rarely involved in a fight, he is strong enough to take care of himself and smaller teammates as well. And his checks can be devastating. It was Potvin who racked up the Rangers' Ulf Nilsson in February, causing a broken ankle that still has nilsoon on the injury list.

Earlier, Potvin suffered a shoulder separation against the Rangers, but there was no hint of foul play in either incident.

"I like to think other players respect me as a relatively clean hockey player," Potvin said. I Check hard, without elbows or dirty shots."

Potvin's biggest goal is to play on a Stanley Cup winner, something that seemed remote when he joined the Islanders in 1973, after the club had posted a 12-60-6 record, hockey's worst until the Washington Capitals were born. He has been a key factor in the Islanders' turnaround, however, and the regular season title this year showed the team is capable of beating anyone, even it up. Game 3 is scheduled Tuesday night in Madison Square Garden with tickets priced at $22, and Potvin is ready for a war.

"We know we have to work damn hard to get anything from them," Potvin said.

Meanwhile, in Boston, the Bruins are faced with a 2-0 deficit as they entertain Montreal in the third game of the semifinal. Another defeat and the Bostom media will be turning its attention to the future of Coach Don Cherry, whose contract is expiring. CAPTION: Picture, Denis Potvin