Cassano is undergoing surgery on a fractured hand.
"My hand really hurts still, even though it has improved since the surgery. I think it'll be fully recovered in about 20 days," he told La Gazzetta dello Sport.
"Of course, this is nothing compared to what happened to my heart. That problem made me understand many things about the world, because when you're between life and death, it makes you see things differently.
"I realised that you cannot have regrets in life. I think I've given all I could and I'm happy with what I achieved in 15 years of my career."