Ralph Sampson will undergo arthroscopic surgery to remove torn cartilage in his left knee on Friday and will be sidelined for at least four weeks, the Golden State Warriors announced.

Sampson, slowed twice previously by arthroscopic surgery to his right and left knee, re-injured the knee during the first half of the Warriors' loss in Portland last Friday night. He is averaging a career-low 8.3 points and seven rebounds in 24 minutes per game this season.