even if milos won his 2 singles matches you'd have to count on likely vasek winning one of the other rubbers and i dont think he could
and then it would come down to doubles and at this point spain has a stronger combination for a doubles team then we do
at the closest id give it 3-2 to spain
and why wont nadal play?
The timing of the rubber combined with Nadal's recent injury and likely an attempt on his part to reduce the number of matches he plays means that there is a very good chance Nadal won't play (not guaranteed, but I'd put it well above 80%).