I am playing a game where 2/3 of my roster get called up for National games. It always leaves me with players playing out of position, and I get killed. What happens if I refuse to let them go? Will they be pissed and I will have to trade them?
I always refuse to let first-team players go play in a friendly if I have a competitive game. I don't know if they'll get angry on FM11, but in FM10 they usually didn't get upset.
There's usually a friendly between the MLS conference final and final on FM 2010 too, kind of annoying when most of your roster are jetting off to play for Canada and the US. I usually just put 45 minute restrictions on my players, I found they played better without the "slight concern: is upset you didn't let them join the national squad" etc, but then again I also just like to see their cap count grow.
Oh, I only withdraw them if the callup DIRECTLY conflicts with a competitive match (i.e. by playing in the int'l friendly they'll actually miss a real match). If it is midweek or whatever, ya I usually set them to 45 mins.
I don't usually coach teams that have too, too many international players. So when they do get called up I happily let them play for their country.