Dont worry, I inderstand you...Look.. lets do it like this.. if a player was +8 (X=8)then they say that the X weeks injured (8)...will be X games that the player would not play.. (2 plays per week, 8/2=4) so now is 4 weeks with 8 plays missed..
League matches and Cup matches.
we added in doctors skill into the formula which determines how severe the injury is (including the chance that the injury doesn't translate into an injury which lasts longer than the game).