Ex-UFC Star Brendan Schaub Rips Greg Hardy, His Run Will End Soon! |

STEP IT UP

Greg Hardy's had a nice run to start his fighting career ... but it'll all come crashing down as soon as he stops "fighting bums" -- so says ex-UFC star Brendan Schaub.

We got the UFC fighter-turned-MMA analyst out at LAX ... and he pulled no punches when it came to breaking down Hardy's fight career -- both present and future.

"There's other guys I would market over Greg Hardy for a number of reasons," Schaub says.

"He's not young, he's fighting bums."

Brendan says he sees Greg's run -- which has already featured 3 devastating knockouts in 3 bouts -- coming to an end as soon as he gets to "those real killers in the UFC."

In fact ... Brendan tells us if Shawne Merriman and Hardy go toe-to-toe in a scrap that they both want -- Schaub says he's got "Lights Out" in the match.

"I'll take Shawne," Brendan tells us. "He's a better football player, so maybe he's a better fighter."