Adrian Peterson's begun training for his celebrity boxing match with his poker rival ... and while his hands could certainly use some more sharpening, it's clear he's in great shape.
Check out some videos TMZ Sports has obtained of the Minnesota Vikings legend as he kicked off his preparation for his big matchup with Joe "Baby Joe" Castaneda ... he looked like he could still pick up a few first downs for an NFL team.
Rockin' a maroon tee, grey shorts and black shoes .