Lee isn't going to happen. His contract is insane, 25M each for the next 3 year and 12$M buyout option.
Clay contract in comparison is a drop in the bucket. His options comes post the Beckett and Lackey era. The Sox has just Buchholz right now under contract after 2014 as far as starting pitching is concern. Barnes and Workman will be making minimum in between. This leave plenty of room to get FA starters.