The incident happened just before midnight on Wednesday at the junction of Route des Quennevais and Rue Carrée in St Brelade, when a dark blue Ford Fiesta suddenly came to a stop in the middle of the road, the States police said.
The front-seat male passenger allegedly got out of the vehicle, opened a rear door and dragged a man outside and assaulted him.
The force said the two men ended up grappling on the grass verge at the junction with Pont du Val.
Following the assault the suspect got back in the car and it was driven off towards Les Quennevais. The alleged victim, who is aged in his 50s, suffered minor facial injuries which were treated by hospital staff the following morning.
A suspect was arrested and later released on bail.
Anyone with information, particularly the driver of a car which stopped as the incident unfolded, is being asked to phone the States police on 612612 or Crimestoppers on 0800 555 111.