LeBron James hit the court for the first time during the preseason, but the Cavaliers lost to the Bulls 108-94 at Quicken Loans Arena.
James tallied 17 points and five rebounds in 30 minutes, but also turned the ball over eight times.
He missed Cleveland's first four games with a sprained left ankle. James started alongside Derrick Rose, Dwyane Wade, Jae Crowder and Kevin Love for the defending Eastern Conference champions.
The Cavs close out the preseason against the Magic Friday in Orlando.