Sliding into a base is not necessary. So, can you actually explain this, or are you just taking the broad "nothing in the game is actually necessary" stance? Within the realm of what's necessary, there's no discernable difference between sliding and diving/leaping. A guy can stand up and be tagged out at a base just as easily as he can pull up and play a sinking liner on a bounce. You're beyond ridiculous at this point. The likelihood of sliding working out balance out the risk. Laying out to make a catch is such a long shot that the odds of things going wrong (injury, turning a single into a double or more, etc.) are way too high when compared to the likelihood of making the play. That's BS. Diving for a ball in the outfield is not a long shot play, nor is it a high injury risk play. As to the first, I'd completely unscientifically estimate that OFs come up with about half of the diving catches they attempt. Maybe a bit more than half. Doesn't seem long shot to me. As to the second, I'd need it explained how the injury risk from diving in OF grass is higher than the risk of sliding headfirst into second base, where there's a fielder to collide with and a base to jam a finger/wrist on. If I'm beyond ridiculous, then you're doing a horrible job of explaining why. From what I can tell, you're drawing completely arbitrary and indefensible boundaries for what is acceptable risk on a baseball field (batting, sliding, blocking the plate, etc), and what is not (diving/leaping in the outfield).