I don't see any reason why moving the mound back a few inches would cause more injuries to pitchers. In fact, it might give pitchers a fraction of a second longer to react when a screamer gets hit at them.
Really though, move the mound back and LOWER it slightly to counter the increased velocity. The lower mound height will also likely reduce injuries to pitchers. Reduce the seam height on the ball a tiny bit, deaden it a little, and allow pitchers to use an approved substance on their fingers for grip. Oh, and stop allowing teams to create short porches like in Yankee Stadium.