The Liverpool striker is ready for Spain's friendly with Uruguay, after an 11 month absence from the national side.
"In the last 11 months since I was last called up there have been some important changes in my career," he said.
"When I was at Real Madrid I hardly played and it was difficult to play for the national team and when I arrived at Liverpool I had some initial problems with my fitness and in adapting to the training.
"Now everything is going as I hoped it would."