I am training 1 specific player for about 3,5 seasons now, and the only times when he didn't get 48 minutes from the coach where
1) when I took more then 9 players to the game
2) when I played fast paced tactics.
3) when he got injured, or had 6 fouls
his stamina isn't too high. But with low paced games he always gets his full game.
I always put that guy in the 3 spots for his position in the roster, starter reserve and back-up, and tell the coach to strictly follow the chart. I don't fill out ANY other reserve spot. and get EVERYone who is taken to the game a spot in the roster, either as starter or back-up.
This should work every time, unless you have 1 of the 3 above.
They are not your friends; they dispise you. I am the only one you can count on. Trust me.