Just 20 minutes after Georgetown's season had ended here Thursday night with an upset loss to James Madison in the NCAA tournament, the Hoyas' only senior, 7-foot center Mike Frazier, smiled and issued the following warning:

"Opponents beware," he said. "Georgetown will be the Beast of the East."

Frazier has good cause for such optimism. With Coach John Thompson having recruited high school all-Americas Patrick Ewing and William Martin, and every starter returning next season, including all-America Eric Floyd, expectations will be high for the 1981-82 Hoyas.

Thompson talked about next season with a little less glee. "I'm not going to stand here and tell you that I'm not aware we have got good kids for next year, but after this loss, it's just died and you start talking about getting married again.

"I've tried to caution myself against thinking too much about next season, because it would be unfair to these kids. I just haven't let myself think about it as much as some say I should."

But now that Georgetown's season is over, Thompson has months to ponder how the addition of Ewing and Martin will improve the Hoyas.

"We won 20 games this season and made it to the NCAA tournament," said Floyd, who, despite playing on an injured left leg, scored 22 points in Thursday's 61-55 loss to Madison. "So we certainly don't have anything to be ashamed of. I'd term the season successful but we definitely have to go back and analyze why it wasn't better. And I have to see what I could have done better, as an individual."

It's doubtful Floyd could have done any more. He produced 35 percent of the team's offense, sometimes reluctantly. The junior guard averaged 19 points per game and was relied on all season to take most of the important shots.

But teams that live by 18- and 20-footers often suffer the fate the sluggish Hoyas encountered against Madison. Georgetown had no one to count on for the big basket from within the lane with the game on the line.

With the 7-foot Ewing and the 6-8 Martin demanding a great share of defensive attention inside, Floyd should be even more effective next year. Ewing will be the first truly gifted center that former pivotman Thompson will have had the chance to coach. Ewing's addition also will allow 6-9 Ed Spriggs, this year's starting center, to move to power forward, where he will be more effective.