Two police union honchos are so outraged the NFL threatened to sack a Titans linebacker for wearing a patriotic pair of cleats honoring those who died on 9/11, they promised to pay his fine if he wears them in Sunday’s game anyway, The Post has learned.

Avery Williamson, a starting linebacker for the Tennessee team, hoped to wear a pair of specially-designed cleats at his team’s home opener Sunday against the Minnesota Vikings on the 15th anniversary of the 9/11 attacks, but he backed off when a league rep vowed to fine him for violating the league’s uniform code.

The left cleat says 9-11-01, with the 11 in the outline of the Twin Towers, while the right one says Never Forget.

“I don’t want to draw negative attention, so I’m just going to focus on playing the game,” Williamson told the Tennessean newspaper, on Friday.

The news outraged Paul Nunziato, head of the Port Authority Police Benevolent Association.

“I’m making a goal line stand on this. Enough is enough! The NFL is out of bounds on this,” he insisted.

He said that NFL Commissioner Roger Goodell, by denying Williamson the right to wear the patriotic footwear, had “committed a personal foul against humanity.

“This guy [Williamson] was hoping to honor everyone who died on 9/11, no matter what their country or color.”

Nunziato has teamed up with Patrick Colligan, president of the 33,000 member New Jersey State Policemen’s Benevolent Association, who was equally flabbergasted about the threatened fine.

Both union leaders say they’re urging Williamson to reconsider and wear the cleats – and the two unions will pay his fine.

Read more from The New York Post.