Adrian Peterson -- The Smiley Mug Shot [UPDATE]

2:20 PM PT -- Peterson has lawyered up ... and his new attorney, Rusty Hardin, has released a statement ... claiming the NFL star did NOTHING wrong. In fact, Peterson claims HE is the real victim:

"Adrian Peterson did not resist arrest this past Saturday morning and any suggestion that he pushed, struck or shoved a Houston Police officer is a total fabrication."

The statement continues, "He, in fact, was struck at least twice in the face for absolutely no legitimate reason, and when all the evidence is impartially reviewed, it will clearly show Adrian was the victim, not the aggressor."

TMZ has obtained Adrian Peterson's mug shot ... taken moments after the NFL superstar was arrested for resisting arrest in Houston, Texas last week.

Peterson -- sporting a goofy smile -- was arrested after allegedly shoving an off-duty police officer in a Houston nightclub early Thursday morning.

The general manager of the nightclub tells TMZ ... Peterson was HAMMERED that night ... which is completely out of character for the Minnesota Vikings running back, who has a reputation for being a very low-key guy.

We're told Peterson apologized to police after the incident.