Priefer said in a statement: "I owe an apology to many people, the Wilf family, the Minnesota Vikings organisation and fans, my family, the LGBT community, Chris Kluwe and anyone else that I offended with my insensitive remark.
"I regret what has occurred and what I said. I am extremely sorry but I will learn from this situation and will work on educating others to create more tolerance and respect."
An investigation into the allegations found that the coordinator made a single anti-gay statement to Kluwe, who spoke out in support of same-sex marriage during his time with the Vikings.
The Vikings have said that Priefer will be able to reduce his ban to two games if he attends anti-harassment, diversity and sexual-orientation sensitivity training.