The celebrity news Web site said police investigated the incident outside the Sayers Club in Hollywood early Wednesday and consider the case closed unless the man Lohan hit contacts them later and reports an injury.
TMZ said the person she hit was the manager of the nearby Hookah Lounge, who was in the parking lot with patrons and photographers when Lohan was trying to leave.
Lohan, 25, is a former child star with a string of hits behind her such as "The Parent Trap," "Freaky Friday" and "Mean Girls."
But her once-bright career has been eclipsed in recent years by legal problems stemming from her addictions to drugs and alcohol. She went through rehab and is on the comeback trail, having served as guest host on a recent episode of "Saturday Night Live" and been cast as screen icon Elizabeth Taylor in a TV movie.