I disagree with that philosophy. CF prospects with any sign of a bat should be able to hold down a corner. MI prospects with any sign of a bat should be able to hold down a corner. A LF, RF, 3B, 1B with signs of a bat have less room for error because there is less available to slide down to on the defensive spectrum. Just like a SP prospect always has RP to slide down to if struggles persist. Not to say ALL up the middle players can play corners, or ALL SP prospects can thrive in relief, but they have a better shot than the inverse.