CHICAGO -- As Chicago Bulls guard Lonzo Ball approaches the two-year anniversary of his last NBA game, his coach Billy Donovan said the team is hopeful the former Laker and Pelican can take a major step in the rehab process next month.

Ball, who has already been ruled out for the entire 2023-24 season, is expected to begin running in January, Donovan said before Thursday's game against the Indiana Pacers.

"The pain that he was experiencing that was causing the setback has been eliminated," Donovan said.

Ball, who has been rehabbing in Los Angeles, was in Chicago last week to check in with the team. He has not played in an NBA game since Jan. 14, 2022, and has had three separate arthroscopic knee surgeries since. Yet, following a cartilage transplant in March, Ball arrived to training camp saying he was optimistic about his recovery and vowing to play again.

"I give him a lot of credit," Donovan said on Thursday. "His disposition has not changed at all. It's really remarkable. And not to say that he's carefree, because he's not. I know the guy wants to be out there playing. The game's been taken away from him for a couple years now.

"But his attitude and the optimism that he is going to get back on the floor, I appreciate. Because when you go through what he's gone through, it's very easy to sit there and start to doubt and question.

"But hopefully in January he'll start running, that's the big thing. But everything they've done in terms of progressing him, he's handled very well."

Donovan said Ball has mostly been limited to some stationary shooting and different mobility and weight training, so running would be the biggest stress test on his surgically repaired knee.

Ball appeared in 35 games during the 2021-22 season, his first in Chicago, averaging 13.0 points, 5.4 rebounds and 5.1 assists. He missed all of last season and was ruled out of this season at the draft this past June.

The Bulls received a $10.2 million disabled player exception for Ball this summer.