Don't worry about the formation and strategy, change that when the match starts and you are only at risk first few minutes of the game. Plan before the first match on which players you will use green packs, which players you will substitute, write it down and then do that in those 2 minutes. I managed to make changes from my phone in the same situation on 2 occasions. I planned everything in detail before the first match and hope that the injury doesn't mess up your plans. Good luck and I agree, very frustrating..