An interesting theory that Saiz and Heras have been exploring is maybe Heras performs better in his second Grand Tour in a given year than his first (maybe because Heras always does well in the Vuelta), with the possibility that the second is somehow aided by Heras' having participated in the first.
Therefore, they are thinking about having Heras possibly ride the Giro next year, so that the Tour would be his second Grand Tour of the year instead of his first. The problem with that approach is what happens to the Vuelta, if it would be Heras' third Grand Tour participation next year? I guess, if he wins 05 Vuelta, Heras would want to defend properly in 06. If he does not win the 05 Vuelta, Heras would want to try to break the record (I'm not sure about the record point) and have the most Vuelta wins in history by trying for a Vuelta win in 06. So, given the importance of the Vuelta in 06 either way to Heras and given his historically better chances for success in the Vuelta than in the Tour, how would Heras and Saiz decide among the three Grand Tours?
"Q: Manolo Saiz has pointed towards the possibility that next year you could ride in the Giro before the Tour, what do you think of the idea?
Heras: It’s a theory based on the experience of recent years, in which I have not been able to perform well in the first major tour but I have in the second. After a first great effort I may feel better. For the time being, nothing has been decided, we shall see next year."
http://www.libertyseguroswurth.com/prensa_1.asp?opc=2&ide=78
"Q: Roberto Heras was not able to reach his level, how do you rate his performance? Saiz: ... The fact that [Heras] has not been able to perform well in the Tour in the last two years [his only post-USPS years] has made us consider him riding the Giro next year, which doesn’t mean that he will not ride in the Tour again, as some people have interpreted, but maybe after doing the Giro he could come here with some other kind of guarantee, because we believe that Roberto could be a rider with second strengths, as he proved in the Vuelta."
http://www.libertyseguroswurth.com/prensa_1.asp?opc=2&ide=77