As many as three NFL legends could be throwing hands on the upcoming Adrian Peterson fight card … as Le’Veon Bell just told TMZ Sports he’s got interest in boxing Frank Gore at the event.

We caught up with the former Pittsburgh Steelers tailback out at LAX this week … and given he once knocked out Peterson in the squared circle, we had to ask about the upcoming tilt between A.P. and his poker rival, Joe “Baby Joe” Castaneda.

Bell said he believes his ex-NFL colleague will win … before he informed us he’d actually be down to mix it up in a bout just before the Peterson vs. Castaneda main event.

Like Bell and Peterson, Gore has entered the celebrity boxing world in retirement — logging a couple fights in the past few years. No word yet, though, if he’d be down to step in between the ropes to get it on with Bell later this year.

Fight with Gore or not, Bell seemed to be genuinely curious about how Peterson will fare versus Castaneda … considering he believes the ex-Vikings star got beaten up a bit in their May fistfight over cards.

“I would think AP will win this,” he said. “But, like I said, it’s boxing. One punch can change everything.”