His TJ surgery contributed to the Red Sox winning the World Series last year. If he just went on like he did in 2010 for the next 4 years pitching poorly because of a pre-existing injury the Red Sox knew about, 2013 likely never happens the way it played out.
Red Sox got what they bargained for. Lackey did as well. I am pretty sure Lackey signed the deal knowing he only plays that last year if he had plans to play baseball beyond 2015. If he doesn't, he is under no obligation to play in 2015 and his contract does not compel him to play, so he should not play. If he wants to play beyond 2015, he has no choice but to play in 2015.
Red Sox got what they bargained for. Lackey did as well. I am pretty sure Lackey signed the deal knowing he only plays that last year if he had plans to play baseball beyond 2015. If he doesn't, he is under no obligation to play in 2015 and his contract does not compel him to play, so he should not play. If he wants to play beyond 2015, he has no choice but to play in 2015.