CHICAGO -- Initial tests run on Chicago Bulls center Joakim Noah's injured right thumb revealed a sprain, according to a league source.

It is unclear whether Noah will have to miss any time or will be available to play Friday night against the Memphis Grizzlies.

Noah injured the thumb during Wednesday night's win against the Detroit Pistons. He didn't want to go into detail about the injury after the game, calling it just a "boo-boo," but he did wear a protective brace on it as he headed out of the Palace of Auburn Hills.

The Bulls have to be extra cautious with the injury. Noah has become their most valuable player and is in the midst of the best stretch of his career. He racked up his second triple-double in three games in Wednesday's win as a focal point on both ends of the floor. More importantly, Noah tore ligaments in the same thumb during the 2010-11 season and had to miss two months after having surgery to repair it.

The key for the Bulls will be to see how he responds to treatment. He has shown a high pain threshold in the past, having played with the ligament tear for almost a month before having surgery in December 2010.

Bulls coach Tom Thibodeau is expected to update Noah's condition after Friday morning's shootaround.