Think yaya is getting unfair stick.
Not his fault pellegrini picks him every match.at his age we should save him for the big matches and bring him on as sub, not overplay him.
He has proved he still has it,just give him a regular rest,why buy all those midfielders and never rotate yaya.
Surely we don't need yaya in the early stages of the cups etc., we bought Delphi because of his work rate, put him to work, give him more game time and cherry pick using yaya.
If he needs a rest then he should say hes unfit beforehard. I wouldn't be surprised if he has a clause in his contract that states he must play when he is declared fit.
On top of that, if what you say is true, it doesn't warrant doing nothing for 80 minutes of a game.