Tyler Colvin is doing terrible and the Cubs don't need him. For some reason this is a tough decision for Mike Quade, but to me it seems obvious.
Send him down to triple-A. What's the point in stashing him on the bench so he can't get better? You're too worried to play him anyway because of his struggles. Honestly at this point he never should have been called up in the first place. He did pretty good last year for a rookie but didn't help the Cubs accomplish anything.
It's also running up his arbitration clock, which will make him cost the Cubs more money to keep. Sending him to the minors will post-pone that clock. After this year Fukudome will be gone, and Colvin can play then. If Colvin starts doing awesome in the minors, you can trade Fukudome and bring Colvin up.
What is hard about this?