Guys, I'm sure that many already noticed that this year FM version demands to pay more attention to the squad building area in order to have any success in the game because players get tired sufficiently more between matches than before and also, there are a lot of injures and red cards so as I said to have any success in the game you must build your team that way to be protected against those issues.
I recommend you to have no less than 3 players for every position but it doesn't mean that you should have exactly 3 players for every position because one player might cover few positions, for example, your Shadow Striker might play Wide Midfielder position and vice versa.
Train your players to play many different positions because it might be very helpful.