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.
I'd say that could be pretty good advice about the game pace.
I usually single-position train and quite often have the problem of my trainee getting subbed out after 46 minutes or so. Obsiously, the no-brainer options like strictly follow and play with fouls were checked, no reserves or backups selected, and usually with 8-9 players dressed. Sometimes I'll even see my starting 2-guard come in to replace my trainee who was supposed to be playing 48 at centre. To be honest I don't think I've tried setting the trainee in all three slots for his position, but from what others have said in this thread that may or may not help.
I usually play push-the-ball which could be contributing to the problem I guess. In the past I'd wondered if it was a stamina issue but it's happened for guys with decent enough stamina as well as those without.