I wouldn't play them in the reserves at all, drop them completely, as he did with Kev Penny. (not that I agreed with that scenario in that particular case..as i actually think playing with reserves will help rebuild Kev's confidence.
Why should the young ones lose their place to someone who isn't performing.... unless they replace them in the 1st team of course..
I wonder how many of the young ones would want to play in the 1st team at the moment,,,