Tom LaGarde, who must have been making Seattle forget Marvin Webster what with the Super-Sonics currently boasting the NBA's best record, has gone down for a count of 12 to 16 weeks.

The night Phil Ford showed the Bullets his NBA credentials in streak-busting style, his former fellow UNC Tar Heel, the 6-foot-10 LaGarde, collided with 76er Harvey Catchings in Philadelphia and twisted his right knee. That was Saturday. Sunday night, LaGarde was operated on for torn ligaments and yesterday Sonic Coach Lenny Wilkens began shopping for "a man with experience" to fill in.

LaGarde had started 22 of Seattle's 23 games this season, averaging 11 points and 8.3 rebounds and was leading the club on the offensive glass -- not bad for a fellow whose other knee had been torn up during his senior Carolina season two years ago and who, although Denver's first draftee in '77, saw but limited action for the Nuggets. They happily shed him in exchange for Seattle's No. 1 pick this year.

Forward Jack Sikma slid over to pivot and bombed Philly for 29 points, 20 rebounds, so it may not be total disaster for the resourceful Wilkens. But how about that, three UNC '76 Olympians -- LaGarde, Ford and Washington's Mitch Kupchak -- keying first-place teams in three of the NBA's four divisions?