I usually control them myself in preseason, ensuring everyone I'm planning to use in the months ahead, gets gametime. When the season starts, I want the whole 1st team squad to be matchfit, not only a slect few. So during friendlies, I rotate a lot, use all 12 subs, etc.
Also, I might have trust-issues I don't trust my ***. manager to pick up on everything, giving me reports and feedback that is 100% correct. But that's my problem...