Jordan Poole is set for a big contract extension with the Golden State Warriors -- something he's supposedly made known around the team's facilities -- and it's the reason things boiled over with Draymond Green ... TMZ Sports has learned.
Sources who were at the practice where Green punched Poole tell us ... in the days leading up to the incident, Poole was carrying himself differently -- in a cocky manner. The alleged behavior was creating friction between him and some of his teammates, including Draymond, who has reportedly also asked for a big extension.