The starter never gets tired - unless you are the starter. Its even nicer when you ran your team down the field and once nearing the goalline you get substituted and the substitute makes the TD
Have been like that for ages now and will probably NEVER be fixed by EA - like so many other annyoing things...
Back to the original question, did you try pressing X on Coachs Trust and visit training after reaching 100% trust for the next level? That usually helped, whe I got stucked - at least on my PS3 ...