Nabru asked why Justin Smoak's Def value on Fangraphs was a negative, if he's viewed as a an above average defender at first base.
You hypothesized that he is not a good defender, and cited his lack of range as the reason why his Def value is negative.
That actually isn't true, and I explained why. Very few first basemen will accumulate a positive rating because of the positional adjustment. Def can be used to compare the value of all players relative to their position. A negative Def rating at first base does not equate to poor defender.