You could argue its to try and justify the fee, but for me, its just that Pellegrini does not trust youngsters. He will only play them in "safe" games (i.e. the early rounds of the League or FA Cup against modest opposition, or in games when we're 3-0 up and its the last 10 minutes) or when he has absolutely no choice because of injuries or suspensions. Anything else and no, he'll always pick a more experienced player like Bony or Demichelis, even if they've done absolutely nothing to justify it. Its not just Kelechi. Celina set up Aguero on his home debut against Leicester, and looked lively, yet he's just vanished, same for the youngsters that impressed against Chelsea, in Pellegrini's protest team selection; Faupala goal on his debut, Adarabioyo decent performance against Chelsea, Manu Garcia showing promise, also Deneyer and Roberts sent out on loan, leaving us with Demichelis, and Navas unchallenged as our only right sided winger. Pellegrini has probably also given Bony "his word" that when fit, he's the second choice striker regardless. And we all know Pellegrini would rather lose then break his word.