There is no timeline for surgery.
Cousins’ visit to team physicians in Los Angeles on Thursday confirmed the diagnosis, which constitutes a third serious leg injury in the past year and a half.
Cousins, a four-time All-Star, already had his mobility compromised with a left Achilles tear in January 2018 and a quad tear in April.
Cousins, 29, was working out in Las Vegas on Monday when he had to leave the court after what one source described as “bumping knees” with another player.
Cousins signed a one-year, $3.5 million contract with the Lakers in July. He was expected to be part of a Lakers team expected to be among the NBA’s elite this season. In his nine NBA seasons, Cousins has averaged 21.2 points and 10.9 rebounds a game.
He signed a one-year deal with Golden State, where he spent most of the season rehabilitating the Achilles injury before playing 30 regular season games — and injury a quad in Game 2 a of the Western Conference playoff series. He returned in Game 1 of the NBA Finals against Toronto.