Chicago Bulls’ Lonzo Ball (2) blocks the shot of Brooklyn Nets’ Blake Griffin (2) during the second half of an NBA basketball game Wednesday, Jan. 12, 2022 in Chicago. The Nets won 138-112. (AP Photo/Charles Rex Arbogast)

CHICAGO (AP) — Chicago Bulls guard Lonzo Ball will undergo left knee arthroscopy and is expected to be out six to eight weeks, the team announced Thursday.

Ball has missed three games since a 42-point loss to Golden State last week. Coach Billy Donovan said Wednesday the team had changed his treatment, hoping he would avoid surgery, after he didn’t respond well to the initial regimen. Ball had the same knee checked in 2018 when he was with the Lakers.

Acquired from New Orleans in a sign-and-trade deal, Ball was a major contributor to Chicago’s rise to the top of the Eastern Conference. He is averaging 13 points, 5.4 rebounds and 5.1 assists. A disruptive defender on the perimeter, he’s sixth in the league in steals at 1.8 per game.

Chicago (28-15) was tied with Miami for the lead in the East through Wednesday after four straight losing seasons. The Bulls travel to Milwaukee on Friday to begin a three-game road trip that also takes them to Orlando and Miami.

With Ball out and star Zach LaVine (aching left knee) sidelined, the Bulls are leaning more into Coby White and rookie Ayo Dosunmu.