Khabib Down to Box Floyd Mayweather After UFC Contract Ends

Khabib Nurmagomedov only has 1 fight left on his UFC contract -- and if that final UFC fight is not a bout with Floyd Mayweather -- he'll schedule it himself when he becomes a free agent.

This is the plan according to Khabib's manager Ali Abdelaziz who says Khabib is still deadly serious about taking on Floyd in the BOXING ring.

Remember, Dana White slammed the door on Khabib boxing Floyd, while he's still under contract with the UFC ... claiming if Floyd wants a piece of the Eagle, it'll be in the Octagon.

Ali tells TMZ Sports ... Khabib will respect Dana's wishes while he's under contract, but, once his deal is up, they're willing to contact Floyd directly and hash out a deal for a 2019 fight date.

If Floyd does agree to an MMA fight, Ali warns the guy to save up for life insurance -- "because he’s not going to be walking anymore. He’s going to be drinking water [through a] straw."

Ali claims he isn't trying to go around Dana -- he wants to work with the UFC -- but clearly feels there's too much money at stake to blow off a potential Mayweather fight.

Floyd previously told us a fight with Khabib would "definitely" score him a 9-figure paycheck -- and Khabib's side would be significant too.