If Bahrain Merida does OK in the TTT, and loses say 30 seconds, and Nibali loses one minute on PdBF, he would presumably be still within striking range for the podium at that point, as there are a lot of stages left. I would argue that if he loses two minutes on PdBF, he would still be in striking range for the podium, but that would be about the limit from my perspective. Not as much because of the time, although that is certainly a problem, but because of the number of riders who would be ahead of him. While he has some record of success in the ITT, it is not such that one would expect him to gain time on all of his rivals for the podium, and the gain he would have on some of his rivals would be fairly limited. So it would come down to whether he is a better climber than all but one of two of his rivals, and he would have to be significantly better than them to get to the podium. A tough ask, I would say.