I think it was an absolute shock to convert him from a SS to an OF in the first place, however, he's proven this season that any type of obstacle doesn't detract away from him in other facets of the game (which unfortunately has happened to many). Therefore, returning him back to the middle IF shouldn't pose to be a major shock to the system since it seems Upton is invincible.
I'd rather have CarGo or D'Antona up now than Hairston. At least D'Antona is thriving offensively and I believe he can continue his assault at the ML level. Why keep Hairston? Yes, he's out-of-options, but he definitely needs a change of scenery. He's still a defensive liability and continues to swing at the first pitch or pull off the ball. True, he hasn't committed too many errors, but still makes the wrong turn on routine fly-balls and constantly misses the cut-off man. Yes, he's still not an OF, but lord, at least he does better there than 2nd base, but of course that's not saying much.
I'd rather have a defensive liability that can hit like D'Antona opposed to a player similar to Hairston he performs way beneath his natural potential in every area.
CarGO will be the type who excels more at the ML level than he ever has in the Minors. I think he will prove his worth and distance himself ahead most of all that have gone before him (meaning Quentin, CoJack, and Drew).