Mirotic has yet to recover from the strained quad and swollen knee he sustained when getting into a scrum for a loose ball in Game 2.
While Mirotic watched his side beat the Bucks 113-106 on Thursday night from the sidelines, he has started shooting again, which is a positive sign for his team.
However, the bad news is that he has not done any running since Friday afternoon.
Bulls head coach Tom Thibodeau made it clear that he will not risk playing Mirotic until the rookie makes a full recovery.
"We don't want to jump ahead," Thibodeau told reporters. "If he's ready to play, he plays; if he's not ready to play, he'll sit. It's that simple."