For the past few years, I've found ways to make sure I made it a point to draft David Bush and bury him on my fantasy team until he starts to come around. Some say it's a waste of a draft pick, some agree that there's something about Bush that you've gotta take a chance on.
David Bush is well-regarded as a fantasy baseball "huge sleeper", even if his stats don't look gleaming because of the low wins and high ERA. What makes him a favorite was his usually "good/great" K/BB and low WHIP.
Andy, in my mind, fits the same mold as Bush. Great K/BB and WHIP, but the high BAA-ERA-BABIP keep him from posting great "fantasy numbers". Is he a good pitcher? For the most part, but just unlucky to start his career.
While people like Hammel because he has a projectable body and "great stuff", he's more of a project than a player. Sonny fits the Shields mold, in which the player doesn't have the greatest "stuff" but his understanding and control of what he has makes him lethal and exciting to watch.