Those are definitely things that should get caught in the editing process - and even in the self-editing process before the book goes to an editor. The issue about the football is a copyedit and proofreading issue. Copyedits are supposed to correct things like spelling, grammar, punctuation, etc., while proofreading is supposed to correct any differences between the written material and the copy that goes to print. Errors like this are fairly common in first editions of novels, even from major publishing houses. Subsequent additions should have all or most of these errors corrected.
The "cups his hands and shouts" issue is a bit trickier, and may have to do with changes from the first draft to later drafts, where major story elements have changed. Say the first draft was a version where the guy didn't lose a hand. Writing "cups his hands and shouts" then makes perfect sense with the story. Now the author, on subsequent drafts changes things up, the hand gets lost, and he has to go back and ensure all of the rest of the book from that point on lines up with the fact he only has one hand. Something like that is easy to miss. And while that should get caught in edits later on, it's easily enough missed there too. This kind of thing happens all the time, in essentially every book out there. The fact such errors don't show up more often is a tribute to the professionals doing the editing.
It's all attention to detail. And it's easy enough to miss a word or two when one is dealing with 80,000 to 100,000 words, or in the case of epic fantasy and science fiction, a whole lot more even.
World Champion Seattle Seahawks football. It's an addiction, and there is no cure.