MINNEAPOLIS (AP) — Former Minnesota Viking Matt Birk has proclaimed his support for an amendment banning gay marriage in Minnesota.

Birk appears in a web-only ad and also wrote a commentary for the Star Tribune on Monday detailing his stance. Birk says he views the definition of marriage between one man and one woman as sacred.

And he says making same-sex marriage OK will affect his children and the welfare of society.

Birk said he wants to clarify that not all NFL players think redefining marriage — quote — “is a good thing.” Vikings punter Chris Kluwe has been a prominent opponent of the amendment.