Injuries

We hear the Rams have this great medical staff. So what's with all these guys going down? Never understood the Van Jefferson second surgery. Was the first one a bad one?
If it was a clean up why isn't he back? The Rams said he'd be back for the first game and then he misses the whole beginning of the season. And why so many of our OL hurt?
And our DBs? I can see losing a quarter of the starters from sickness, but injuries? Everywhere? What are the trainers doing? McVay has coach-speaked his butt off and nothing makes sense. Did they work hard enough this off season? Did they stretch? Did they run? Looks like they partied and just showed up.