If you trade Kaz Matsui and he has a ROY season like Ichiro did his first year in the US, you will kick yourself.
Kaz is a seasoned veteran, Crosby is a very promising rookie. I'd bet on Kaz because Crosby is unproven. Also, IMO Oakland is coming down to earth this season.
Why not wait and see how they do in April? It's a long season and whoever you drop may turn out huge.
3andOut: Whenever I feel blue, I start breathing again.