Man, sorry to hear about that. It's heart warming that you were going to go out and play ball with him a little bit one last time. Not many people would do that. That's good on you, it shows you have heart and character.
I dunno what you're beliefs are, but I am half American Indian and live much of the way they do as far as religion goes. I have a medicine bag I keep little snippets of feathers or fur from critters I have loved and lost. By now it's a little late for you, I imagine. Just know deep inside that it was not only for the best but he has very much impacted you as a person and it shows, therefore he is always with you.