The Washington Bullets, trying desperately to get back into the playoffs, yesterday traded second-year man Roger Phegley to the New Jersey Nets for high-scoring guard John Williamson and "future considerations."

The future consideration is believed to be the Nets' second-round draft choice in 1982.

Some National Basketball Association sources say the Bullets and the Portland Trail Blazers are close to a deal that would send Mitch Kupchak to Portland with Maurice Lucas coming to Washington.

"We have talked to them (the Bullets) about Kupchak," said Portland Coach Jack Ramsay. "We haven't come to any decisions, but we could in a day or two.

"We're concerned about Kupchak's back and we've done some exploration into the situation. When he is healthy, Kupchak is one of the best big men in the game. He needs proper conditioning and the opportunity to play."

League sources say the two teams have also discussed a possible deal involving Greg Ballard and Lucas.

Bullet General Manager Bob Ferry said last night, however, that no deal had been made for Lucas, but added that he has talked to Portland about him. "A lot of people are interested in him," Ferry said.

He would not say what Bullet players were discussed in a possible trade.

Williamson, 27, reached in San Antonio where the Nets will play the Spurs tonight, said, "I have no comment whatsoever until I get back to my home."

"Williamson was the best player available to help us," Ferry said. "We're in a situation in the season where we had to figure out where we were and where we were going. We had to either continue like we were or make a move to give us a shot at the playoffs.

"We're getting Williamson to score points. I believe it's the best move we could have made and I hope and think he wants to come in and play basketball."

Ferry said Williamson was flying home to New Jersey late last night and that he hoped he would join the Bullets in time for today's practice.

"This is just a sheer gamble," Ferry continued. "We are a team that is struggling and I don't think you can consider our odds good to make the playoffs. We had to do something."

Phegley left last night for San Antonio and said he planned to play for the Nets tonight.

"I cerntainly enjoyed being in Washington, but I wasn't really satisfied with the way I was being used," Phegley said. "All I can do now is try to make the best of the situation. I know New Jersey is having some problems. I'll just go in with the attitude that I can help them.

"Everyone knows the Bullets had to make a trade quickly and that they needed someone who could help them right away," Phegley added. "I just didn't think I would be involved.

"I bit my tongue and never caused any trouble before, but this is a bit sharp. I don't leave with any hard feelings, though."

Phegley, a part-time starter this season, played both small forward and big guard. He scored 35 points in the second game of the year against the New York Knicks, but has been inconsistent most of the season. He leaves with an 11.3 average.

The 6-foot-3 Williamson, nicknamed "Supe" for "Super John," was very popular with the New Jersey fans. But he was not a favorite of management, particularly Coach Kevin Loughery.

Williamson went into this season with a 22.2-point NBA scoring average after three years. He is averaging 17.4 points this season, but missed 20 games when he was overweight and Loughery refused to play him.

Williamson has one more year to go on a $185,000-a-year contract. He wanted it renegotiated to $300,000 a year; the Nets countered with a $235,000 a year offer.

When they reached an impasse, Williamson started gaining weight. His normal playing weight is 205, but he ballooned to 228 at one point this season. He is down to about 215.

He was not suspended for the 20 games he missed, but he was not with the team. He came back Jan. 23 and scored 19 points in 27 minutes against the Cleveland Cavaliers.

Since his return, Williamson has played in six games and averaged 18.5 points as a reserve. At Denver on Thursday, he scored 28 points in 26 minutes.

Williamson is not considered a good ball-handler, but the Bullets apparently do not care. They want him to score.

"He's great offensively," said an NBA source who has watched Williamson all season, "He can really help the Bullets if he keeps his off-the-court stuff under control."

Defense is not Williamson's strength, either. But the Bullets feel that Phegley and starter Kevin Grevey have had defensive problems, too, and that Williamson's offense will more than make up for his lack of defense.