Why the Celtics are getting a bargain on Payton Pritchard’s two-year, $44.2 million contract extension

Getty Images Upward mobility in the NBA contractual market is pretty rare. A player’s financial destiny is often tied to where he is drafted. Where that player is drafted frequently determines the opportunities he gets early in his career, which in turn determines his rookie extension, what he’s eligible for on his next deal and so on. One team-friendly contract tends to beget several, and nowhere is that truer right now than it is for Payton Pritchard. On Tuesday, he and the Boston Celtics agreed to a two-year, $44.2 million contract extension, according to ESPN. All told, that will guarantee…