This is an interesting decision for the FO but I think ultimately the best thing for the organization is to ship Chacin back and have Cook regain form and pitch lights out. Now seeing as I too have many undeniably possible but not likely fantasies going on in my life, I don't wish to be disappointed and I say Chacin gives us a better chance to beat teams even going through his rookie mistakes and Cookie has become a 6th starter and should go long Guy and spot starter.
Tough call, I'd like to hear ya'alls take.