Starts to get complex when the first teamer you are replacing decides he’s too good to sit on our bench and wants to leave, or causes hassle in the dressing room. These aren’t just chess pieces that can be moved where you want them to go.
I don't think in terms of a first 11 anymore - a team has to rely on about 16 regulars with a back up of another 6 or so, particularly this season with game frequency.
So that means players need to be confident they can win a place in the first x1, but also accept rest/recovery time when they miss a few matches.