Future -- Calls Out Russell Wilson -- You're NOT My Kid's Father!!!

Future is NOT happy with that photo of Russell Wilson pushing his son in a stroller -- saying if he was the kid, he would've jumped out and SLAPPED Russell in the face.

The rapper appeared on "The Breakfast Club" and told Charlamagne tha God he's upset with his baby mama Ciara for allowing her new BF to get so involved in the parenting their 1-year-old.

Future blames Ciara for setting him up -- but still blames Russell for trying to insert himself into his kid's life after only dating Ciara for a few short months.

"At the end of the day, I'm not for the publicity stunts. Leave my son out of the publicity stunts. Just leave him out of your relationship."