I watched parts of several games today and all of the PL sides put out very weakened teams. This is why prices to watch are reduced. Nigel Pearson said that he wanted to find out about some of his fringe players, but I am not sure that you can get a real impression of if a single player will fit into your settled first team when required if they are part of a team put together that doesn't really have a regular mode of playing.
As one of our number told the Tranmere fans forum, "While you won't be seeing the likes of deulofeu I think Pereyra will start and he's a rolls Royce of a player." Today he looked more like a broken down 2CV. On that form Pearson would surely wonder if he is worth keeping as he doesn't look right since his injury.
As a lover of the FA Cup it saddens me to watch the demise of it, but all teams in the PL will put staying there the priority simply because of the money.