Foot and ankle problems can be prevented with preseason screenings to potentially strengthen muscles like the peroneals and observe abnormal gait patterns that can be precursors to sustaining certain injuries. In these cases, the individual must go on an individualized strengthening program that helps support the weaker areas. Knee pathologies can be prevented by a greater gluteus medius and VMO strengthening programs.
There is no excuse for muscular strains on professional athletes. Very preventable pathologies. But you are right in that Ribs, collarbones and concussions are not preventable by strengthening programs. Something that can and should be done to help prevent these injuries are more extensive equipment fittings to assure the helmet, rib guards and shoulder pads are a perfect fit for each individual player. This is the NFL they have more than enough money to purchase new equipment for player safety and have no problem doing so. If you take a look into other NFL organizations you surely do not see as many fractured ribs as you do in Green Bay and Washington. That is not by coincidence that you see certain teams sustaining the same injury. This indicates that the equipment and training staff are not working together to properly fit each player to a rib guard. Of course the player also has a lot to do with this, as many players do not strap their rib guards, but it is not by accident that teams like the Patriots have two players in Chris Hogan and Trey Flowers take a shot in the ribs and Only sustain a contusion (bruise). A player that is 6’6 should not be wearing the same size rib guards as a player that is 5’10, should he? My fiancé has a tiny head (Big head I mean lol) and my head can’t fit in any of his hats. If we are both wearing a helmet that fits me, and we take a shot to the head, he is more likely to sustain a concussion, right? It’s simple ergonomics, though I must note the NFL as a whole has gotten much better about helmet fittings in the past year or two (for obvious reasons).