Dave Portnoy Says Mahomes Sr. Vs. Rocker Fight Canceled, Claims Brittany Torpedoed It

Dave Portnoy says the scheduled fight between Patrick Mahomes Sr. and John Rocker is now off ... and he's alleging Brittany Mahomes' meddling is a big reason why.

The Barstool Sports honcho broke the news of the celeb boxing match's cancelation during an appearance on "The Unnamed Show" Friday ... explaining Brittany and Patrick Mahomes II's agent torpedoed the whole deal.

According to Portnoy, just a few days after his "Rough N Rowdy" promotion announced the Mahomes vs. Rocker contract ... the two arguably most close to the Kansas City Chiefs star quarterback stepped in and put a stop to things.

"Mahomes' agent, the football player, and Brittany -- from what I am told -- intervened and were like, 'There's no way this fight's happening,'" Portnoy said. "'We're going to cut this guy off if he does it.'"

Court documents TMZ Sports obtained revealed Mahomes Sr. agreed on Jan. 17 to fight Rocker in April ... and then "staged" an altercation with the former MLB star on Bourbon St. during Super Bowl LIX week earlier this month to drum up interest in the bout.

The docs stated Mahomes Sr. was slated to earn at least $85,000 for the scrap.

Portnoy seemed peeved that it's all now sunk ... as he insisted the fight was entirely Mahomes and Rocker's idea.

"They came to us to do this," Portnoy said. "How would we ever come up with this concept. Like, Oh, let's put John Rocker vs. Pat Mahomes Sr. Like, who would ever think of that?"

"They came to us and said they hated each other and wanted to fight."