The 20-year-old has not made a senior appearance since joining the Citizens in 2015 and impressed on loan at FC Twente last season
Manchester City forward Enes Unal is set to join Villarreal in a deal worth €15 million, Goal understands.
The 20-year-old joined the Premier League outfit in 2015 but has not made a senior appearance for the club.
He has spent time out on loan at Genk, NAC Breda and FC Twente, with his performances for the latter particularly impressing.
He scored 18 goals in 32 Eredivisie appearances for the Dutch side as well as laying on a further four strikes.