Risk of injuries can go down with the state of the field and the medical facilities if I am not mistaken. Other then that there is no info on how injuries occur. It is pure random. When the injury storm hits, you better duck. I hope you can watch some animations to get some red packs. Otherwise sell some injured players and get some new ones. Only way to get your team back up to full strength.

Side note: I see that you are training a lot of special abilities with players that will take forever to get those abilities. If you want to train a SA then get 18-21 young players who are fast trainers. Search for fast trainers in this forum how to spot them. The older the player gets the less exp he will earn. The difference between a young fast trainer and a 26 yr old player could be something like 60-100%.