Lorenzo Williams, who has played only 33 games in three seasons with the Washington Wizards because of injuries, will undergo arthroscopic surgery soon on his right knee injured during workouts a month ago.

The Wizards also officially re-signed forward Randell Jackson, who had agreed to a deal last week.

The decision to remove loose cartilage from Williams's knee follows an examination of the knee by team physician Steve Haas yesterday. Williams, a 6-foot-9 center/power forward, bumped the knee in summer workouts here with other players about a month ago. The injury was not considered serious at the time, but he still has "swelling and a lot of pain," agent Steve Kauffman said. Wizards officials said Williams will need three to four weeks of rehabilitation, so he will miss at least the first week of the team's training camp that opens Oct. 4.

"Lorenzo told me that he was anxious to get this problem behind him and contribute on the basketball court for the upcoming season," Wizards General Manager Wes Unseld said, "including his excitement to move to the power forward position."

Earlier this week, after the Wizards lost free agent power forward Grant Long to Vancouver, Unseld said he considered Williams one of the candidates to compete for the starting job in training camp.

"It's a shame," Kauffman said, noting that Williams had recovered from all his previous knee, foot and leg problems and was healthy until the latest injury.

Washington signed Williams to a seven-year, $14-million contract in 1996. The Wizards hoped that he would be a bargain, based on two solid seasons with the Dallas Mavericks, finishing 11th in the league in blocked shots and sixth in offensive rebounds in 1995-96. He did not play last season because of foot problems.

Meanwhile, Kauffman said the Wizards last week signed another of his clients, free agent Jason Lawson, a 6-foot-11 center and power forward, to a one-year, $460,000 contract.

Lawson, a onetime starter at Villanova, was cut by Orlando in the preseason last year, and played for Grand Rapids in the CBA, where he dominated the playoffs as a scorer and rebounder until his team was eliminated.