This season I have not to much complains about injured players (miracle), compared to the earlier 2 seasons, 4 or 5 injured so far (not bad at all), but what I've noticed is when I collect some free red boosters ~ 19-21 is more than certain that I'll have a injured player in the next one or two matches.
In the earlier seasons (2 in my case), I bought dozens of red boosters to make a decent formation teams for the matches.
So I've decided this season, not to invest anymore tokens in those boosters and it seems it will works fine so far, the injured palyers has dropped and I've saved a lot of tokens.
That's a strange coincidence or not, who knows?...