This is incorrect! Greenburg was thought to never appear on screen but in Season 1, Episode 6, "Heart Moniter" Greenburg makes an appearance. Just past 24 minutes into the episode you see Scott, Stiles, and Allison in coach's class. He tells them to settle down because they were going to start discussing the reading. A few kids volunteer to share what they learned, but coach says, "Greenburg, put your hand down, everybody knows you did the reading." The shot is of the entire class and only three boys have their hands raised, and on of them puts their hands down after coach says this. The boy who puts his hand down is Greenburg!