The Sonics’ bench brigade might soon be getting a companion with size, muscle and NBA experience.

“We’re close to signing a guy,” Sonics coach George Karl said after Friday’s practice.

Neither Karl nor Wally Walker, the Sonics’ general manager, would say who the team is pursuing in its attempt to add interior muscle to complement forward Shawn Kemp and center Jim McIlvaine, or whether the move involves a trade.

Both club officials said the transaction could occur this weekend and Friday night the team placed Steve Scheffler (torn plantar fascia in his right foot) on the injured list.

“We have been looking for additional depth up front all season,” Walker said. “I would characterize our most recent conversations as more serious.”

Walker said the player being pursued has NBA experience.

Brian Williams? Probably not.

The 6-foot-11 free agent who averaged 15.8 points and 7.6 rebounds for the Los Angeles Clippers last season, has a new agent, a bad knee and wants a lucrative contract.

Karl said the Sonics’ target is someone who “leans more toward (being) an impact (player) than it does Antonio Harvey.” The Sonics signed and released Harvey this season.

The coach also said the starting lineup will remain the same. “You don’t fiddle with it unless you’re losing,” Karl said.

Although the Sonics (25-11) are playing well and riding a four-game winning streak heading into tonight’s game at KeyArena against the Indiana Pacers, the future would look much better with a bigger backup at center.

The 7-foot-1 McIlvaine is averaging 3.9 points, 3.9 rebounds and 2.3 blocked shots in 19.5 minutes per game.

“We are playing a young center more minutes than I thought we would be playing him,” Karl said. “We need another guy.”

Since the Sonics waived Harvey a week ago, 6-8 Larry Stewart has been McIlvaine’s primary backup.

Nearing the halfway point of the season, Karl said he is still trying to figure the best way to use his backups.