Complex sentence: Prior to his enrollment at UMass Amherst, Allen played his junior hockey with the Sioux Falls Stampede of the United States Hockey League (USHL) as was a graduate of The Latin School of Chicago.
Split into simpler sentences: Prior to his enrollment at UMass Amherst, Allen played his junior hockey with the Sioux Falls Stampede of the United States Hockey League (USHL). Allen is a graduate of The Latin School of Chicago.