Guardiola told reporters at the Club World Cup, after leaving Grealish out of his squad, via ESPN: "He had a conversation between him and the club and they decided it was best [to stay behind. Jack is an exceptional player. The only reason why he didn't play last season is of course my decisions. We decide that he has to play. The club was honest, he was honest.
"We decide the best is to stay [behind] and have a place that he can feel like he can come back to be the player like he was in the year of the treble or all his career in Aston Villa. The fact is in the last two seasons he didn't play much minutes. He has to come back to play and have the butterflies in his stomach that he can play every three days, every three days and show again the quality he has."