I read through this 'guide' on how to reduce injuries and they missed out something important.

Play your reserves in less important games. such as preliminary/qualifying/playoff rounds of the cup that you know you are going to win easy for example, protecting your best players from being injured in these games against low ranked teams that do nothing but cause injuries. Or play your reserves in CL group games when you have already qualified from the group (or been knocked out) or play some reserves when you've won (or lost) the 1st leg like a score of 6-0.