1. Is that column actually dWAR? It's just labeled "Def". I always though it was some sort of calculated run differential, given the numbers involved in the don't always correlate so well with the WAR values. Not really much of a counterpoint, I was just wondering.
2. That's actually not how average works. Just being 10th of 22 doesn't necessarily make you "above average." In this case, the average value in that DEF comumn is 7.8, so Bogaerts is right on the cusp, being the top name above the delimiting line. But given margin of error, he is probably about average. But if the 9 names above his all were credited with a total of one more point each - something completely independent of Bogaerts' fielding - Bogaerts would actually be below the calculated average. Would that make him "below average"?
Really, if we have legitmate arguments for him being above average and below average, he is probably about average. And with his offense, that is more than acceptable...