How normal is the level of injury we're seeing in the preseason?

Only been keeping up for this past season, Lions are my home team, been keeping up with their news. Various Lions players have been taken out of practice for multiple different injuries. Rondale Moore on the Falcons has a season ending injury, concern for J.J. McCarthy on the Vikings, more that I've not taken note of the names. I'm at least aware that football is very injury-heavy, so some of this shouldn't be a surprise.

Is this an abnormally high amount of injuries for NFL preseason/practice? Or is this about what you'd expect, and people are just doomsaying?