As you say only 2 good central defensive midfielders. So shouldn't we be holding onto Ball as back up for Field,? He has already played the 1st part of the season doing exactly that. There were times we looked very open in front of the back 3, improved with Field's return, but I don't think Amos, Thomas or Dozzell are CDM's. Dont remember seeing Sanderson had played there before either.But only 2 good defensive CDs...Ball and Field.
( I'm sure Sanderson could play there I suppose).
I suspect we have made the decision that we are "strong enough" defensively ..so Ball can go...but not strong enough attacking...so to add variety ( and after a couple of good cameos) Thomas can stay.
Ball will always be applauded by me in the future..like Pugh before him...always tried and gave his best...a very good servant to QPR