In the Giro Uran was in a good shape, yes, but he was working, and he lost 1 min 30 seconds waiting for Wiggins. He like hot weather and there was cold, really cold and rain in the mountains. And the real hard stages of the Giro, those who make the difference, were suspended or changed by one climb stage. Anyway Nibali was the stronger than Giro, he was really strong, but it would be another race in other conditions, and Urán still can improve.
Anyway Urán is not very reliable, if he is not in the best shape, in three weeks he can lose time one day and say bye bye.