Golf, in the second grade Bum, Jr.'s elementary teacher asked each kid to write down what they wanted to be when they grew up.
Bum, Jr. wrote down an MLB pitcher.
He's not there yet, may never be, but he has never waivered from his dream. Growing up, I would ask him nearly every week, "Do you still love baseball?" He always said yes. I told him that's great, that as long as the answer was yes, he would have to dedicate himself to work twice as hard as the competition. There's no half-way.
Re-read your post. Your son has already told you he doesn't want to do it.
I'm talking about the mental aspect of baseball, which I believe is critically important. You want your kid to have dreams. Okay, is it his dream? Figure this out first, then you can discuss with him the plan to get there.
Dream. Plan. Do.
What level of the pro's is Bum Jr. at now?