Troy Tulowitzki was the best defender in Major League Baseball last year by almost any measure I have found, he also was statistically the 2nd Best offensive rookie in Baseball. He lost the ROY to Ryan Braun who posted better offensive numbers but was the worst defender in Major League baseball. The only argument I have run across is that Tulos Home/Road splits were too disparate to see awarding him ROY or taking his offensive stats to seriously.
A similar issue arose when Matt Holliday was not awarded MVP despite winning 2 legs of the Triple Crown and finishing 4th in the third. Holliday again had similarly large differences between Home and Road numbers and the same argument that he is overrated persists. Can you judge if these two are as good as I think they are or are they as overrated as has been claimed