Sage Northcutt tipped the scale at 170 lbs. on Friday ... but he'll be a helluva lot heavier in the future -- as in, the size of a 206+ lb. heavyweight -- 'cause that's where Super Sage says he'll eventually fight.
TMZ Sports talked to the UFC star before his co-main event fight against Zak Ottow at Saturday's UFC Fight Night 133 -- a fight in the 170 lb. welterweight division.