I don't think who starts these first few preseason games says much at all about who will start or be here long term.
To me, it looks like Parcells is using these preseason games to get some decent experience for the young pups. How valuable will these first few games be for those kids who were able to start a couple of games if they are thrown into the mix mid-season because of an injury?
Take Romo for instance. Wouldn't you feel better now if Bledsoe was unable to play for a few games? Same with all the o-lineman. Get the kids out of diapers as soon as possible in case you need them down the road.
IMO, I think Fabini gets cut and Parcells keeps youth and will rotate them in as much as situations allow. While Fabini has some experience, he's got no upside and no one is claiming he's been any more impressive than any of the young kids.
We'll see.