This surprised me. Maybe it's PR, a way to get fans to the games at Indy, but I'm surprised Dean Treanor is quoted as saying, "I wouldn't expect he'll be here very long." And later in the article, "I think they want him to face some more veteran pitching before they call him up, but I really don't expect him to be here an extended period of time."
I'd be surprised, barring injury, if Marte were called up any time before July and it wouldn't surprise me if he wasn't called up at all. There is little point in having him up in September unless it is clear he is going to be starting on Opening Day 2013 because they can better manage his service time.
Having said that, performance will hopefully will dictate most of what happens. I just don't see how Dean Treanor is benefiting anyone by putting a timeframe on things. But then again, maybe he knows something we don't.