Alex Poythress is the big man on campus at Clarksville Northeast High school, even if it’s not by choice. Such is life when you’re a six-foot-seven All-American basketball player signed to play next season for John Calipari at Kentucky. Poythress finalized the decision in November. His signing was greeted with the typical exaltation the Big Blue Nation reserves for a big time recruit – he is a consensus top 30 player in the various national rankings…