NFL's Christian Kirk May Have Been Coked Up, Cop Says In Police Report

NFL rookie Christian Kirk was showing signs of cocaine use when he was arrested at a golf tournament in Arizona back in February ... this according to the police report obtained by TMZ Sports.

Kirk -- a 2nd round draft pick by the AZ Cardinals -- was arrested for criminal damage to a car on Feb. 3 after cops say he was throwing rocks at cars in a parking lot outside of the Phoenix Open.

Event security had contacted police and said the suspects were "high."

When the Scottsdale PD arrived to the scene, one of the officers "immediately noticed Kirk's demeanor. He had a blank stare."

The officer placed Kirk under arrest and handcuffed him -- and then suggested he may have been on cocaine.

"I further noticed the grinding movement of his jaw and continued blank stare. These are common signs of an individual high on stimulants, such as cocaine."

Both Kirk and another man were transported to a nearby police station where they were booked and later released.