My choice would depend on what I would give up.
Since Garza is "the man you build your rotation around" I would see at least Kalish and Middlebrooks and if you rush me Lavarnway in Cubland; I don't like that my friend. If you don't give up Kalish, make the deal.
On the other hand you have Kuroda and Oswalt. IMO they will cost you +-12 M/year. Yes, they will cost you go over the LT, but at least you keep your top prospects, regardless our farm is not that abundant of these kind of guys (Kal, Lav, Mid).