Fatigue cannot be considered a norm because if it does, then there will be no need to bother about it enough to want to rest player so as to prevent it from happening too often. Most times some teams will even put in measures and not let their players who are key to them to embark on such so they do not get to suffer injury back at their national team and coming back to their club to take it.
Fatigue is never a normal thing and it can not be regarded as a norm because it affects the performance of players at such that you get to see a very good player struggling to perform well for his team, clubs don't often let some of their key players to go to represent their national team because they are scared of the players becoming too tired and some being unable to perform for the club due to tiredness which is also associated with fatigue, clubs have a way of managing the players because it they get affected by fatigued it could cost the team a major loss of points.