Without seeing a full roster, league type or scoring I would say stick with Miggy.
I think you could get more then that from Miggy and Hamels. Greinke, imo, is overvalued fantasy wise. No stop, don't bite my head of, he is an amazing SP, but KC can't give him enough run support to make him as fantasy relevant as last year. I really think at best Greinke winds up a top 10 SP and Hamels won't be that far off that pace, if any at all. So that leaves trading Power for SB? Would never do it, as it stands theres a damn good chance Miggy winds up with a better average then Jose anyways, so really the only thing Reyes may beat Miggy in is SB and a few runs, not worth it.
Stick with Miggy and see what else rolls across your plate, because I just don't see Greinke NEAR the value he was last year.
Great thanks to soto for the sweet sig!...