The Arsenal man signed for the Gunners from Barcelona in the summer of 2014 for £35million, and has since been a roaring success at the Emirates.
And Pellegrini, who left Manchester City in the summer to be replaced by Pep Guardiola, said the club were punished by UEFA for breaching FFP rules, and did not have space in the squad for him.
"He was one of the best in the world and he showed it every day," Pellegrini told Chilean radio station ADN. "He was a major player we wanted to take to City.
