Michael Sam -- 'I'm Single' ... Engagement Not Back On (VIDEO)

So much for a reconciliation ...

Michael Sam tells TMZ Sports he and his ex-fiance Vito Cammisano are NOT back together ... despite the fact they hit the L.A. club scene together Sunday.

Michael and Vito broke off their engagement back in June ... 6 months after Michael popped the question.

They hooked back up to shoot an anti-bullying video last month ... and then were spotted out in Hollywood together having dinner and then hitting up a nightclub.

But Tuesday night, Sam told up there's no reconciliation ... and he's still on the hunt for Mr. Right.

Good luck ...