Craig Houston is embroiled in a legal battle with major Ibrox shareholder Sandy Easdale. The 41-year-old father-of-two has received a court summons and a claim for £200,000 in damages.
He has refused to sign a gagging order that would end the court action.
Easdale, a member of the Rangers football board, is unhappy with "libellous" posts on the Sons of Struth Facebook page.
Houston said: "I have received a Court of Session summons and a claim for defamation of Alexander Easdale. The claim is for £200,000 worth of damages to his reputation. I'm just a normal guy. I don't have that kind of money. So if this goes against me I'd have no other option, but to declare myself bankrupt.
"I have also been given an option of signing a gagging order, but these claims relate to posts on our Facebook page by other people. There is nothing I can do about that.
"The only way I could guarantee having no further problem would be to close the Sons of Struth Facebook page. I'm sure that is what Mr Esadale would like.
"But in spite of this threat I am not tempted to do that. This is about what is right and wrong. Morally and legally, I have a strong case.
"But I can't be certain of victory and as a father with two kids the consequences of losing are terrifying. I stand to lose everything. I'd be ruined."
He added: "I've made his (Easdale's) lawyers aware of similar posts made on three other online forums.
"As I see it, my only crime is being vocal in my criticism of the Rangers board. I can't think of another fan of any other club who has been taken to court for not liking the people running their club."
Greenock businessman Sandy Easdale, whose brother James is a Rangers director, said Houston could stop the legal action.
He said: "He's got a choice to end this by signing a letter and agreeing to stop these attacks.
"If he does that then we don't go to court. That is his way out, but he chose to ignore it. That suggests to me he intends to continue spreading detrimental comments.
"I don't want to go to court, but I can't allow this to continue. He's not being picked on.
"If any libellous comments are made on any website and brought to my attention they are acted upon by my lawyers."