Firing a manger during the season could be justified, depends on the situation. With Yost, it may or may not be. None of us know what goes on in the clubhouse. Now, your 2nd question is a good one. No, it's commonplace to fire managers and head coaches without a laundry list of objective, substantiated reasons. Steinbrenner did it for years, sometimes it worked, sometimes it didn't. What did Garner ever do to get fired? You look at all the chronic losing teams in MLB (Rockies, DRays, Royals, etc.) and they make a change basically for the sake of change. I'm not arguing if that's the right approach or not, that's just the way it works in sports. It's about winning, and if management loses faith in you, game over. Trying hard and making the right moves only lasts so long.