Premier division teams in the top European leagues (EPL etc) play a lot of matches, especially the elite teams that also play in UEFA. With player fatigue, injury, suspension etc reserve players must be needed at times. By reserve I mean players beyond the starting eleven plus 3 subs.
My question is who are these players, how good are they and what do they get paid? From the teams perspective, they have plenty of cash and don't want to have to field players who are terrible when their stars are unavailable. But from the players perspective, if you are good enough to occasionally be a sub and get a few minutes for Manchester United, then you are probably good enough to be a starting player for Wolverhampton but then you'd actually get to play full games regularly. Is this about the standard of these reserve players, or are they more like the ability of a regular starter in a lower division?
The main football code I follow is Australian Rugby League and in the top competition (the NRL) each club has a top team but also a reserved grade team that plays in a parallel competition. There is also an under 21s competition which also functions as a type of reserve grade. When top team players are unavailable, someone who has been doing well in reserve grade steps up to the big time and when the top player returns they go back to the reserves but crucially keep getting regular game time. My understanding of European football is that there is not this kind of reserve grade system. So what are the reserve players doing when they are not needed? How do they continue to demonstrate to the manager that they are in form?