Sure, IF you actually hold them down to work on defense or see lefties, two weeks isn't nearly enough. And, to be honest, whether that was REALLY the reason or not, they are going to ACT like it's the real reason. But we've all been down this road a bunch.
But I WILL disagree with you on the ROY stuff. I think they DO think Holliday would be likely to challenge for the ROY, and for that reason he isn't coming up until they are comfortable that the extra year has been gained. If there is much of a chance of him catching whomever is theoretically in the lead (and 2nd place) then Holliday will stay down, IMO. Service time is the real reason he is down, I believe, and they aren't going to risk losing that.