R.J. Anderson of Fangraphs and D-Rays Bay takes a quick look on players who have been essentially average this year. "Borrowing" the idea from somebody else "appropriately named Devil_Fingers," he lists a few average players, some surprising (Jason Bay? Really!), some not (Mark DeRosa), based on Wins Above Replacement (WAR). The Royals' own Billy Butler gets a shout out.
One player who missed the cut was Adam Dunn, who despite mashing the ball this year, is still below average because he plays awful, awful defense in both the outfield and at first base. If Dunn was a DH, however, he would actually be average to slightly above average.