The AFL will investigate an ugly incident at Docklands after Richmond utility Marlion Pickett was touched over the fence by a fan.

Just before three-quarter-time in Friday night's match, Pickett was chasing Bulldogs captain Marcus Bontempelli into the Tigers' defensive 50 before he ran right towards the fence as his opponent kicked a goal.

A fan in the crowd then reached over to apparently mockingly put a hand on Pickett's shoulder, with the dual Richmond premiership player turning around and knocking a drink out of the supporter's hand.

While the fan appeared to be surrounded by Bulldogs supporters, it was not clear if they were wearing Bulldogs gear.

As soon as the siren sounded at three-quarter-time, Pickett made a beeline towards the same section of the crowd where the incident happened and briefly interacted with a security guard.

The 31-year-old had a long conversation with Richmond football boss Tim Livingstone before the final quarter began, which Pickett started sitting on the bench.

Interim Richmond coach Andrew McQualter said it was "disappointing" the incident happened.

"I don't know full details, but it shouldn't happen," he said.

"We love fans in our game, and they're so critical to our game, but our players should never, ever be touched when they're on the football field.

"I think all Marlion was doing was alerting Tim (Livingstone) to the fact that something happened, and just getting security to deal with it and the AFL will deal with it now."

In 2018, an Adelaide supporter was banned from attending games at the Adelaide Oval for the rest of that season after reaching over the fence and touching Bulldogs captain Easton Wood on the backside.

AAP