Is this a good fantasy trade?

For you personally, I would say go ahead and pull this off. Although this might be a rip off in general, you need serious help on OF department. Also, your starting pitching is damn good with Josh Johnson (2nd SP steal of the year with the Best WHIP in the league), Yovani Gallardo (36Ks in his last 4 games), and Zack Greinke (Won 3 of his last 4 games with his next 3 starts up against Mariners, As, and Yankees who had surprising Negative 10 run diffrential against Mariners over the last 2 games).