Aston Villa midfielder Jack Grealish is subject to an internal investigation by the club following reports of his involvement in an all-night party, manager Roberto di Matteo has said.
At 07:45 BST on Sunday, police were called to a Birmingham hotel as guests complained of a rowdy party, which the Daily Mail reports Grealish attended.
No arrests were made and Grealish, 21, was not one of up to 12 people ejected.
"We are aware of an incident at the weekend," Di Matteo told BBC WM 95.6.
"We started an internal investigation about it, which is still ongoing. When we finish the investigation, we will see what disciplinary action to take."
'Grow up quickly'
Grealish was warned by former boss Tim Sherwood in 2015 after he was pictured apparently taking nitrous oxide.
He also previously spent time training with Villa's youth team as a punishment when Remi Garde was in charge at Villa Park, after reports he visited a nightclub following a 4-0 loss at Everton.
"Unfortunately it has happened again. We expect our players to behave in a professional manner at all times, so it is something that we don't tolerate," added Di Matteo.
"It's important that he understands what he has, and he needs to grow up very quickly."
The Solihull-born former England Under-21 player signed a new four-year deal with the Championship club on 7 September.
Villa owner Tony Xia contacted Grealish directly via the social media platform Twitter on Wednesday, saying: "As I said before, focus every minute, on and off the pitch, choose the right people to be with."
Xia added: "It's not a warning but just elder brother's talk. I trust Jack can really learn and be a man."
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