Can't really blame Hart ... he's a hardcore Eagles fan and he had just watched his team beat the New England Patriots live in Minnesota.

But when they brought him on the "NFL GameDay Prime" post-game show with Deion Sanders and company ... he was hyped up, slurring and, really, 3-sheets to the wind.

After Deion personally escorted him off the stage, Hart left ... and made a drunken Instagram video trying to explain himself. It's pretty hilarious.

Enjoy the hangover.

FYI, Hart was also straight-up REJECTED trying to sneak into the Eagles' post-game celebration. Probably for the best.