THE SIDELINES : Nunn Seized on Traffic Warrant After Run-In With Armed Driver

Michael Nunn, the International Boxing Federation middleweight champion, has been arrested on a traffic warrant after he chased down a motorist who had rear-ended his Mercedes. The man later threatened Nunn with a knife, according to police.

Dan Goossen, Nunn’s manager, said the boxer aggravated a back injury in the crash and would be examined by doctors later this week. A scheduled Jan. 27 fight between Nunn and Marlon Starling was canceled last month when Nunn allegedly injured his back in a fall at his home in Agoura Hills.

The traffic accident occurred in Van Nuys late Saturday night, police said. Nunn’s 1989 Mercedes was struck by a car driven by Nicholas Munoz, 57, of Van Nuys. Munoz, police said, then drove away from the scene, with Nunn driving in pursuit. The boxer eventually forced Munoz’ car to the side of the road, and both drivers got out of their cars.

Nunn told police that Munoz then pulled a knife on him. When officers arrived, Munoz had a bloody nose. They did not know whether Nunn had punched the other driver or whether the injury occurred in the collision.

Nunn was arrested when a computer check showed an unpaid speeding ticket he had received in December. He was held briefly in the Van Nuys jail and then released when Goossen posted $3,000 bail.

Munoz was charged with felony hit-and-run driving, assault with a deadly weapon and suspicion of drunken driving. He was still being held on $2,500 bail in the Van Nuys jail today.