Should I trade Carlos Gonzalez for...?

Billy Butler and Zack Greinke? It's a keeper league. My OF's after Car-go are Sam Fuld, Colby Rasmus, and B.J Upton. Greinke would join Josh Johnson and Clayton Kershaw as the aces on my team. I could use the SP help as well and Butler seems to be a hitting machine. Seems like a fair trade to me. Thoughts? pin ions? Thank you!!