My old college roomate The Big Swede (Brian Miller) is from Wisconsin, and we have a standing bet with the Cubs and Brewers, so a 4 game sweep is a good thing.
Brian was a discus thrower at Northern Arizona, and at a track meet vs. UTEP they had a discus thrower from Sweden.
You know how discus throwers grunt when they throw?
This guy grunted, only like a Swede so it sounded more like "YEEERRRRRRRR!"
Later, when Brian told the story, he got the nickname.
Plus he's a big blonde guy anyway.