There are some players who are prone to injuries
It means weak body structure
3 years ago I played with a last division team two friendly games for fun with my friends whilst i ve had never been playing football for 10 years before the friendly game took place.Even without proper warm up.When the game ended, we lost 8-7 at first game, and 22-1 at second(At second game we didn't have professional footballers in our team) but many players from the opposition and some of my friends got injured
That means weak body. There are footballers made of glass, their body can't bear the pressure and get exposed consistenly for example Simunovic and Rogic they can't play on atroturf
These players need extra care so the solution is to protect them while you can or improve them with more training.If they are trained to the higher level as you claim then we should have been in the last 4 of CL