Baseball players understand how options and all work. It's fanciful to pretend that a 26 man roster is "the best 26 men available", when in fact, there's guys you don't want to lose because they're out of options, signed a major league deal, etc. If a rookie doesn't understand that, and decided he's going to give up because somebody else got an opportunity he thought should have been his, he probably would fail after the first bad strike call on him.