After submitting his name into the NBA draft, Purdue center Isaac Haas announced late Tuesdday night that he's withdrawing and will return for his senior season. His decision - which came well in advance of the May 24 withdrawal deadline - leaves Purdue with forwards Caleb Swanigan and Vincent Edwards still in the midst of the process. Haas worked out for at least two NBA teams, the Oklahoma City Thunder and Boston Celtics. And likely more.