Manchester City expressed "disappointment" after Benjamin Mendy admitted hosting friends at his house on New Year's Eve in a breach of Covid-19 restrictions.
City said they would launch an internal investigation after a report in The Sun said Mendy allowed a chef and two friends of his partner to attend his Cheshire home, despite regulations which prevent people from different households from mixing indoors.
A Manchester City spokesman said: "The club is aware of a New Year's Eve Covid-19 breach involving Benjamin Mendy and the subsequent media reporting of it.
"While it is understood that elements of this incident have been misinterpreted in the reports, and that the player has publicly apologised for his error, the club is disappointed to learn of the transgression and will be conducting an internal investigation."
A spokesperson for Mendy did not deny the claims in a statement given to The Sun.
"Benjamin and his partner allowed a chef and two friends of his partner to attend his property for a dinner party on New Year's Eve," a statement said.
"Ben accepts that this is a breach of Covid-19 protocols and is sorry for his actions in this matter. Ben has had a Covid test and is liaising with Manchester City about this."
A depleted City included Mendy among the substitutes for Sunday's game against Chelsea at Stamford Bridge.
Asked about his selection, Pep Guardiola told Sky Sports: "Firstly, the club made a statement. Secondly, Benjamin has already had Covid, he has had it in the past.
"He has been tested every day like all the guys and he has been negative. He explained, or he said, it was his nephew and his girlfriend and a doctor, a friend of his girlfriend, who were negative too.
"He knows what he has done and he will learn in the future."
City were without several players, including goalkeeper Ederson, at Stamford Bridge after suffering an outbreak of the virus in recent days.
Their match away to Everton on December 28 was postponed at late notice after the number of players affected reached five, and before Sunday's match it was announced that defender Eric Garcia and a member of staff had also now tested positive.
"Both personnel will now observe a period of self-isolation in accordance with Premier League and UK Government protocol on quarantine," a statement said.
"Everyone at the club wishes our colleagues a speedy recovery ahead of their return to work, training and competition."
On Saturday, pictures emerged of Tottenham trio Erik Lamela, Sergio Reguilon and Giovani Lo Celso attending a large house party in London over the Christmas period in clear breach of the regulations.
A statement from Spurs said the club "strongly condemn" the actions of the players, who could now face internal disciplinary action.
West Ham's Manuel Lanzini was also in attendance at the same party. The player issued an apology on social media for his "bad mistake" while the club said the matter had been dealt with internally.
Meanwhile Fulham, whose match at Burnley on Sunday has been postponed due to positive cases at the club, are investigating pictures that emerged on social media on Friday showing Aleksandar Mitrovic and his fellow Serb Luka Milivojevic of Crystal Palace, along with their two families on December 31.
