West Ham’s Lucas Paquetá is being investigated by the Football Association for potential betting breaches, leaving serious doubt over the Brazil midfielder’s potential move to Manchester City. It emerged on Friday morning that Paquetá’s hopes of joining the champions were in major doubt, with a source close to talks attributing the uncertainty to a contractual issue. It would later emerge that the FA has opened an investigation into the former Lyon midfielder over allegations of gambling in football. The nature of the allegations has not been revealed and West Ham and the FA declined to comment. Sources close to the player said they were shocked by the investigation and that Paquetá had not been accused of making bets. West Ham face an anxious wait to discover whether their record signing will be charged. Sources at the club suggested that Paquetá, who joined for £51m last summer, would be available to play in Sunday’s home game against Chelsea. Ivan Toney, the Brentford striker, was banned from football for eight months after admitting 232 charges of the FA’s betting rules this year and is not due to return until January. Paquetá has become a key player for David Moyes and laid on the assist for Jarrod Bowen to score the winner when West Ham beat Fiorentina in the Europa Conference League final last season. He emerged as a target for City this month and they had an initial £70m proposal turned down. Paquetá’s contract contains an £85m release clause that becomes active next summer and City were expected to return with a new bid after losing Kevin De Bruyne to a hamstring injury for months. It is understood that City were close to reaching an agreement with West Ham for the transfer to go ahead before the allegations surfaced. Pep Guardiola is now expected to turn his gaze elsewhere as he hunts for a replacement for Ilkay Gündogan but sources close to Paquetá remain hopeful a deal could go through. City are looking at the Rennes winger Jérémy Doku as a replacement for Riyad Mahrez. West Ham are interested in Doku and had prepared for the likelihood of Paquetá leaving by targeting Ajax’s Mohammed Kudus and Montpellier’s Elye Wahi. Ajax want £44m for Kudus, with West Ham looking to pay a slightly lower fee for the Ghana winger. West Ham have considered handing a short-term deal to Jesse Lingard.