With rosters that small, you can't really help but have only 2 bench warmers. Your bench if fine, except that EE will never play with ARam and Thome blocking his only playing spots. So, if you want to trade someone, he's a great trading chip to upgrade your OF with. I think you should try trading Thome first, though. Even as a DH last year, he had health problems.
If you had to drop a SP, I think you'd have to go with either Buehrle or Lowry. You could always do a 2 for 1 trade to make room as well.