The Sox 40 man roster has 10 players on it I would consider expendable. Weber is probably the highest-ranking (re: least expendable) of those 10.
The other 9 are - in no particular order - Mazza, Springs, Hall, Brice, Walden, Valdez, Stock, Hall, and Hart.
If someone wants to say another player like Wilson or Aybar is more expendable than Weber, fine. Not really worth arguing about as to which AAAA player is the better one. Bottom line is there is a lot of deadwood at the bottom of this roster that can probably be purged (and re-signed to MiLB deals if need be) in order to clear the space for the Sox worthy Rule 5 eligible minor leaguers and a few acquisitions...