This is another one of those questions that I’ve changed my stance on over the years. I used to believe all those throws for an IF’r were too much of a workload for a pitcher and that they’d be better off in the OF from a throwing standpoint. But when you actually look at all the throws an IF’r makes, how many are thrown at the same intensity as a pitch? Now look at the throws an OF’r makes, and I think you’ll see the same thing.
To tell the truth, other than the catcher, I don’t see it as a big deal. And for the catcher, it has nothing to do with the arm, but rather the legs. Its really tough to pitch with tired legs, and if you’ve never caught you have no idea how tired those legs can get! They’re fine to walk on and even run some, but pitching’s a completely different story.