Bankrupt Warren Sapp -- I Didn't REALLY Make That $100k Bet with Rick Ross

Let the backpedaling begin ... 'cause Warren Sapp is now saying he NEVER made a $100,000 bet with rap mogul Rick Ross ... despite strong video evidence to the contrary.

Sapp just went on Twitter and pleaded his case ... saying "just FYI for you clowns, Rick Ross don't even know my Phone # lets alone made a bet of 100k! Sounded Good #Not."

He continued, "I only bet on two things, sure things & my abilities, because the only thing I was ever sure of was my abilities #1stBallot."

Here's the problem ... the two made the bet ON STAGE at a nightclub in NYC ... and then Rick clarified the terms of the wager ON CAMERA (TMZ Sports has the footage).

Plus, they TWEETED about the bet ... with Warren seemingly acknowledging that it was on.

But, as you know, Sapp -- who filed for bankruptcy in 2012 -- took the Denver Broncos ... and they LOST.

As Aaron Rodgers now knows, you shouldn't make bets you don't expect to keep.