2011 was Dunn's first year with the White Sox after they signed him to a 4 year, 56 million deal. They were in no position to do anything but play him with that much money invested. Note: he had 4 errors that year, not 60 - most of his time was at DH, plus some 1B.
As for Victorino, assuming he's healthy enough to play ball at the start of the year, I'm guessing the Sox could trade him easily enough if they picked up at least half of his 13 million salary for 2015.