I found that Injuries in the game at the lower Levels are a lot more common than later on in the game, This is mainly due to the fact that teams are training and playing games on poor facilities.
I am Level 14, and I find most of my injuries are in the cup against lower level teams, possibly due to the poor standard of what those players play at. Theres bound to be a lot more bad tackles, Players aren't as "fit" either and not as intelligent to avoid injuries.