A nickname give to Phil Knight, the founder of Nike and alumnus of the University of Oregon. Phil Knight has donated millions of dollars to University of Oregon Athletics, which has helped pay for state of the art facilities and an overall embarrassment of riches that any athletics program would love to have.. Consequently this has helped Oregon Duck sports (football in particular) become successful. Top-tier athletes are attracted to all of this great stuff. The fans are well-aware of Phil Knight's monetary contributions which have in turn brought success, and metaphorically he's like the uncle whose spoils his nieces/nephews with gifts, hence he's been called "Uncle Phil".
Beaver: "What the hell? How do you guys get all these bitchin' facilities? That's so unfair!!!"
Duck: "It's all courtesy of Uncle Phil. I hope you're looking forward to another beatdown at Autzen stadium where you can see all the new things Uncle Phil has bought for us."