They probably have a rough idea who they think it may be, or a guy they hope is able to keep separating himself, but I don't think we can say with such certainty that they know who the starter is. They've been pretty honest and direct about the team since day one. They've given little to no indication that they're going to BS all of us and the media just for the sake of illusion.
I heard a good point the other day that I find myself agreeing with - if TG is going to win this job, he probably knows he has to do it convincingly. Too little separation between he and Martinez probably favors Martinez because a) he was hand-picked by Lord ScoFro himself and b) he has the dynamic athleticism that TG doesn't. That's why I think the longer this competition remains 'fierce' the more likely it is that Martinez gets the nod.