The Washington Bullets are about to sign former Portland Trail Blazer Billy Ray Bates, a free agent they hope will provide them with the one ingredient they lacked last season -- a proven scorer who can generate his own offense.

"This is just a case of us picking up a scorer," said Bullet General Manager Bob Ferry. "Bates has proven he can score. Whenever we get a chance to look at an offensive guard like him, we're going to do it. He's a one-on-one player, that's for sure, but there's a place in our offense for that."

Bates, 26, is a 6-foot-4 guard who averaged 11.1 points a game last season and has a 12.3-point three-year average, with a career high of 40 points.

His most impressive statistics, however, have come in the playoffs. He averaged 25 points in three playoff games in 1980 and 28.3 in three games in 1981. The Trail Blazers did not make the playoffs last season.

Bates was waived by Portland two weeks ago, even though he had one more guaranteed year on a five-year contract he signed in May of 1981. The Bullets don't owe compensation.

Ferry said he expects to sign Bates to a multiyear Bullet contract in the next couple of days and that Bates probably will report to the opening of training camp Friday.

Ferry wouldn't discuss specific terms of the contract, but it is believed that only the first year is guaranteed.

In another development, the Bullets have called a news conference for 1 p.m. today to announce the signing of their top draft pick, 6-5 guard Bryan Warrick from St. Joseph's.

Bates is considered one of the more spectacular dunkers in the league. His free-wheeling play recently had him at odds with Portland Coach Jack Ramsay. At the same time, his style and enthusiasm made him a crowd favorite.

Ramsay cut Bates after the Trail Blazers tried in vain to trade him. They preferred to stay with younger and more disciplined guards Jim Paxson, Darnell Valentine, Jeff Lamp and rookie Lafayette Lever.

Bates, from Kentucky State, was a third-round draft choice of Houston in 1978. He was waived out of the league and subsequently played two seasons for the Maine Lumberjacks in the Continental League, averaging more than 27 points a game each season.

Portland signed him as a free agent for the final 16 games of the 1979-80 season.

The signing of Bates will give the Bullets an abundance of guards when they start their two-a-day practices Friday at 9 a.m. at Fort Meade. The other guards on the roster are Kevin Porter, John Lucas, Frank Johnson, Kevin Grevey, Don Collins, Garry Witts, Warrick and Nate Davis. Collins, Witts and Davis also play small forward.