I like Whelan, he's missed a ton of bats. Being a non-big-money prospect in the Yankees system is perhaps the worst situation in baseball to be stuck in as far as getting an opportunity at the highest level.
He does appear to have periodic control issues, although it wasn't a problem at AAA Scranton/Wilkes-Barre in 2011 (14 BB, 52.1 IP). Five walks per nine professionally is too many. Still, almost 11 K per nine in 100 AAA appearances as well as over his whole pro career. Originally a fourth-round pick in 2005 by Detroit, went to New York in the Gary Sheffield trade in 2006.