Boumann, who has played two AFL games this season, played in the Box Hill Hawks' 116-point VFL win over Collingwood at Victoria Park on Saturday.
The Hawks confirmed he was involved in an incident at approximately 2.45am on Sunday.
Boumann told the club he was leaving a nightclub with a friend and was looking for a taxi when a verbal exchange with a group of men escalated.
Boumann said he acted in self defence after being repeatedly kicked by a number of people while he was on the ground.
He injured his hand during the altercation, he told the Hawks.
Boumann is required to give a statement to police investigating the incident, the Hawks said.
The incident caps an embarrassing 48 hours for the club, which has also pledged to educate star forward Lance Franklin after he was caught speeding last week.
Franklin, 25, lost his licence for six months after being caught driving at 90km/h in a 50km/h zone on Thursday.
In a statement on Monday afternoon, the Hawks said Franklin would undergo an education program designed to promote "more responsible road behaviour" and donate $1000 towards a road safety program or appropriate charity.
Meanwhile, senior coach Alastair Clarkson has apologised for abusing a runner during a junior football match on Sunday.
Clarkson admitted to using "a couple of expletives" after being instructed to leave the ground.
Clarkson also made headlines during the Hawks' big win over Collingwood on Saturday when he punched a hole in the MCG coach's box wall.
» Click here to watch Clarkson's coach's box rage
Clarkson has agreed to pay for the repairs after the MCG knocked back his offer to fix the wall himself on health and safety grounds.
