In our situation, my son never wanted to dedicate himself fully to baseball until half way through HS. All through grade school and middle school, he participated in a number of sports. He tried out for a travel baseball team here in town, but before the tryout, the coach told him and I, "we already have enough pitching", and wouldn't ya know it, they cut him.
He started taking pitching lessons in 8th grade, because he wanted to. I asked if it was something he wanted to do, and he did. He would do what the pitching coach wanted, work on his stuff at home, with some occasional prodding, but never really showed much drive. Just happy go lucky and let the chips fall where they may. I would talk to him about conditioning, footwork drills, weights, plyometrics, and he would listen, maybe even do it for a couple of weeks, but never followed through, and I never pushed. I would remind him that there were things he could do, but never demeaned him for not doing it.
Then one day, the light bulb went on and he told me that he was going to dedicate himself to baseball. I asked if he would like my help, and he said yes (I know nothing about baseball). My job at that point was to remind him of his commitment. The days he would take off, I'd tell him, "You know, there's some pitcher in your conference that's working harder than you are today, are you still dedicated to becoming a great baseball player, because he is." Is that pressure? Sure it is. It was to prevent the inevitable backslide if he was allowed to revert to happy go lucky. It's easy to talk about dedication, and hard to follow through on it. He needed to learn what it meant, I think he has.