Morales actually broke his lower left leg, is headed for surgery with an ankle specialist, and is likely be done for the season. Apparently he didn't land on anyone, but slipped on the plate when he landed.
While some are going to use this as a reason to stop or at least tone down walk-off celebrations around the game, I just think this was a freak accident. If anything, maybe players should stop leaping onto home plate like Morales did.
Either way, this is a tough break for the Angels, who are already three games under .500 and have now lost their best hitter, likely for the year.