Personally, I am shocked that Dombrowski would trade prospects who the Sox gave bonuses to but are years away for a marginal 4th / 5th starter who isn't better than their hector Velasquez/ Brian Johnson types. I am sure this will marginally improve their position among the As, Rangers , Indians, and Rays for the wild card!
[in fairness, Cashner is better than the guys he's replacing. I'm not sure how much more likely the Sox are to win a WC spot with him than without].
Turn it on its head: why would you accept in trade a pair of 17 year olds who a major league organization paid decent money for, looked at for a year, and then was already fine cutting ties with? They're lottery tickets at best.