Deontay Wilder -- Bring On Shannon Briggs ... If He Passes Drug Test

He's set to fight in January -- though no opponent has been selected -- but WBC heavyweight champ Deontay Wilder says he's got his sights set on Shannon Briggs ... if Briggs can prove he's not on 'roids.

Wilder was SUPPOSED to fight Vyacheslav "Czar" Glazkov at the Barclays Center in Brooklyn on Jan. 16th -- but Glazkov backed out and took another fight ... leaving Wilder without an opponent.

The solution?

"The only person I feel will save this show is Shannon Briggs," Wilder tells TMZ Sports.

Briggs is not only a former 2-time heavyweight champ ... but famously chased Wladimir Klitschko around the world for years trying to Clubber Lang him into a title shot.

Wilder says Briggs would be the perfect opponent -- but has 2 concerns ... cash and drug testing.

"Will he accept the money that we're offering him?" Wilder says ... "Shannon feels he's bigger than he really is ... which he's not."

Wilder's also not convinced Briggs is totally clean ... despite the 44-year-old insisting he's au naturel.