He was one of five players cut from the 28 training with Italy ahead of the tournament in South Africa.
"It has been a very positive experience. I had the opportunity to train alongside great champions and understood the sacrifices made by those who play at this level," said Sirigu.
"All this arrived at the end of a very special season that I will always remember. I played my first Serie A campaign and hope to repeat that performance."
"Training with Buffon was so exciting. He is a wonderful person who works every day with the same determination and desire to improve, despite the fact he's the best goalkeeper in the world.
"As for myself, I am relaxed and aware anything in my future with the Azzurri will depend on my performances for Palermo.
"It will be stimulating to play against some of the top clubs in the Europa League next season. We want to do well in what we consider to be an important competition."