Replacing Gibson will be no easy task for Thibodeau, who had deftly coached the Bulls to a 32-24 record heading into the matchup with the Cavs. The 6-foot-9 Gibson is a rugged defender who is averaging 7.7 points and 5.4 rebounds.
Gibson said the injury gave him more sympathy for Rose, who hurt his knee in the playoffs last season.
"The things he is doing now coming back from that is hard," Gibson said.
AP freelance writer Patrick Rose contributed to this report.
Jay Cohen can be reached at http://www.twitter.com/jcohenap