This trade is AMAZING, possibly even better than the Upton trade. You aren't getting as much compared to the above trade (in what you are giving versus getting), but this improves 2 of your keepers by a good portion. Gallardo could easily outproduce Shields in 2012. Then you get Cargo for Holliday/Zobrist. You would be losing 2 keepers and 1 non-keeper for two studs. Great deal.
Give: Shields, A Bat(this owner was hard in on James, needing pitching) Get: Hosmer, Pedroia
This isn't bad either, but the problem is that you need to cut someone to make room for Hosmer. I'm assuming the bat you move is not a keeper, so does Shields + Another Keeper < Dustin + Hosmer? Who would you be dropping? If it is Zobrist or Santana, I still like it.
Pretty much my only options now are to keep Shields, or the other owner offered Pedroia straight up. That trade would put a kink in my flexibility with having two 3B and two 2B, taking up my util. The league pretty much had a discussion on Shields and killed any value he had left lol. He won't be as good as last year(11 CG? cmon) but he won't be as bad as the year before.
For reference of scoring, Shields scored 922 pts(27.9 ppg) and Pedroia 808 pts(5.1 ppg)