If the Yankees were willing to trade Dunn for A-Rod and swap salaries, would you do it?
The Sox owe Dunn $15m for the next two years ($30m total). The Yankees owe A-Rod 28m/25m/21m/20m/20m over the next 5. ($114m total.)
The salary difference is $84m, which the Yankees would pay to the Sox over 5 years. (An average of about $17m/year)
Sox take on A-Rod's contract, get rid of Dunn, and the $30m they owe from that contract is now paid to A-Rod as follows:
You free up $4m in salary for 2013, $7m in 2014, and have fairly minimal payments in 15,16,17 to the point where you could afford to DFA A-Rod if he is just brutally bad and has become a media nightmare similar to what NY is going through right now. If he is a servicable DH at age 40 in 2015 then you have him for pretty cheap.
I'm pretty sure for 2013 A-Rod at $11m > Dunn + Youkilis at $28m