I agree with what people have posted on many threads in the past about injuries that week 1 and week 4 are the peak weeks for injury. If your squad is big enough let your players heal naturally at the beginning of the season. Save all your red packs and only use them in week 4 when as you point out you need them for the league run in and important cup matches.
I think Khris is right in that i seem to get 1 bad year then a good year injury wise