TMZ Sports talked to 26-year-old Bellator champ A.J. McKee in Tampa, FL on Friday ... and we asked the undefeated fighter about Paul saying he intends to take an MMA fight in the future.

"S**t, he better come train with me, but he can do good," McKee told us.

The 16-0 champ continued ... "If he wanna do it, he can do it. I think he's already shown his skills in what he can do in boxing, so if he wants to take it to a different lane, why not?"

If you missed Jake's comments ... he told the media on Thursday that he "100 percent" was going to fight MMA, saying, "I don't see why if I can do boxing at this high of a level that I couldn't do MMA at this high of a level."

In fact, later that same day, Jake told us he intended to fight and beat Conor McGregor in an MMA cage.

Paul said he going to train at AKA in northern California ... which happens to be the home gym of Khabib Nurmagomedov and Daniel Cormier.

He's very likely kidding ... 'cause DC and Paul ain't exactly buddies. Remember, they nearly came to blows at a UFC event several months back.