According to reports, the player’s 19-year-old brother was elbowed in the head and another member of their group was knocked unconscious during what Northumbria Police called “disorder” at around 4am on Sunday August 20 in Newcastle city centre.
Newcastle United had lost 1-0 away to Manchester City on August 19 and Lascelles travelled back to the North East and went out to Chinawhite nightclub, reports said.
Video of what was said to have happened outside the club, including the 29-year-old reportedly almost being hit by a bottle of vodka, has circulated online.
It was also reported that Lascelles and his group were threatened with being shot.
One of his group was knocked to the floor and required hospital treatment after being knocked out following a kick to the face, it was reported, and Lascelles was punched to the back of his head.
No arrests have been made.
A Northumbria Police spokesperson said: “Shortly after 4am on Sunday August 20, we received a report of disorder involving a number of people on Westgate Road in Newcastle city centre.
“Officers attended, however it is believed that those involved had already left the scene before they arrived.
“Inquiries are ongoing and anyone with information should use the Tell Us Something page of our website or call 101, quoting NP-20230820-0227.”
Newcastle United declined to comment.
Lascelles has been club captain since the age of 23, and has kept the role despite losing his first team place under Eddie Howe, with the on-pitch duties carried out by England defender Kieran Trippier.