Baseball and hockey are the same. MLB and NHL draft more on "rights" to a player, especially in the later rounds. Also, hockey and baseball have more traditional minor leagues, whereas football mainly only has NCAA. In hockey, players drafted to contribute right away, come from the Q, the O, or some pro European/Russian leagues. The college kids that are "drafted" usually graduate from college first and then come and play. NHL and MLB really just retain the rights of said player until they decide to go pro. I'm not AS familiar with baseball, but I think it's about thd same. In football, it's NCAA or NFL. The Canadian and Arena leagues are more for when you're not quite good enough. They're certainly not grooming grounds. In MLB and NHL, they don't sign contracts. They can't or they lose their amateur status and NCAA eligibility. Their rights are just retained by whatever club. Basketball and Football are the same as far as NCAA being the minor leagues for the pros, whereas MLB and NHL have actual farm systems that are professional and no longer amateur status.
Hope that helps.
