Miller is 27 and missed part of 2008 through 2010 with a finger injury. He finally came back last season and put up a 5.93 ERA, a 8.0 K/9 and a 4.3 BB/9 in 44 innings. Before that he was being developed as a starting pitcher and from the ages of 21 to 23 he made 18 starts and 26 appearances, putting up a 4.01 ERA over 98.2 innings.
The Yankees though view him stictly as a reliever. Like Manuel Corpas, Miller would be a on the throw a bunch of relievers at the wall and hope one sticks plan.