Greg Evangelou's company, White Marquee Event Hire, is a principal partner of Port Adelaide.
He made an offensive comment on Facebook, aimed at Adelaide fans who refer to themselves at the "19th man".
"To all my fellow 19th faggots. Enjoy today like you’ve won a grand final ... because that’s about as good as its going to get for yas for a very long time," Evangelou wrote.
The Crows defeated the Power by 23 points on June 29.
The AFL is involved in the matter and treating it seriously. It has offered support to the club and the individual.
"The AFL rejects all forms of vilification and treats this matter seriously," the League said in a statement.
"We will work with the club to ensure this individual understands the harm caused by these types of comments and why they are totally unacceptable."
The AFL has extended assistant to Port Adelaide in counselling Evangelou.
White Marquee Event is reportedly staying on as a sponsor, the Power have also condemned the comments.
After being alerted of the Facebook post by The Adelaide Advertiser this week, club chief executive officer Keith Thomas released the following statement.
"That is most definitely not the type of language or reference we want from people connected with our club at any level," Thomas said.
"We've spoken to Greg and he was extremely contrite and completely understands that he has overstepped the mark on this occasion."
