Choo won't be traded until the Dolan's have to pay him fair market value.
He's arbitration elgible starting this year, and just hired Scott Boras as his agent. Assuming he gets out of his military service, Choo has about a year and a half left in Cleveland before he is dealt.
Apparently the Tribe wanted to lock Choo up long term, but when he fired his agent and hired Boras talks hit a wall.
Boras clients typically get very aggressive during their 3 years of arbitration, and almost never sign extensions that deprive them of free agency after their 6th year of service unless it is some kind of crazy market busting deal. That won't happen from daddy small bucks Dolan, so they will have to trade Choo in about 2 years to get something for him.
His injury probably saved Dolan, because Choo was on pace to be an All-star and have a big season. He would have gotten a massive raise in arbitration next for next year. His stats being down though will make it harder for him to get a big award from the panel if they reject the Tribes offer (which they will because of Boras).