Exclusive Details

Ex-USC quarterback Todd Marinovich -- who also played for the L.A. Raiders -- was arrested for possession of meth in Irvine, CA ... TMZ Sports has learned.

We spoke with Commander Hallinan of the Irvine PD who tells us they got a call about a naked man on the Venta Spur walking trail on Friday night ... and officers eventually found Marinovich in a nearby backyard.

Marinovich was still naked when cops arrived. We're told he was cooperative.

Cops searched the area and found a brown bag containing meth, weed and Todd's I.D.

He was arrested and cited for possession of a controlled substance, trespassing, possession of drug paraphernalia and possession of marijuana. Marinovich has since been released.