Bill Geeslin sat in the stands when the Lakers played in Memphis last Nov. 14. His three-page federal lawsuit filed on Tuesday claims Bryant came off the court during play, landed on Geeslin and "without provocation" committed assault and battery when he struck Geeslin with his elbow.
Geeslin seeks more than $75,000 in damages for unspecified injuries that required medical attention.
Geeslin's attorney, Robert Coleman, declined to elaborate on the filing on Wednesday but said he hadn't been in contact with Bryant's attorneys or agent.
The Grizzlies won last year's game 85-73.