all of the injured players (except the one who got injured in training) had fitness levels above 90, three of them had close to 99.

I am on level 1, since i just started the game 1-2 weeks back. To encounter things like this already makes me cringe at the game and using 15 treatment packs for one player might work - but :
1) ppl on this forum says that its not wise to use these packs as the players tend to re-injure themselves
2) i only have 8 treatment packs in totalt