Former Scotland Captain Gary McAllister has been hospitalized for a while in Leeds.
Liverpool, Leeds, Coventry and Leicester spearhead the assaulted outside a bar in the city center at 4am on Sunday.
The 54-year-old, who amassed 57 caps for his country and captained the team to the Euro 96 finals, reportedly waiting for a taxi with his wife at the venue in Call Lane.
West Yorkshire Police Detective Inspector James Entwistle said, "The initial report was that a man, aged in his 50s, was standing outside a bar when a man approached him and punched him in the face, causing injuries that required hospital treatment.
"We are currently in the process of being in charge of the incident and wanting to know it."
McAllister enjoyed a successful six-year stint at Leeds from 1990 to 1996, during which they became champions of the old First Division in 1992.
He was captain for two years before moving to Coventry, where he would later return after a two-year stay at Liverpool, becoming part of the management team upon his retirement in 2002.
The Scot joins Rangers last year, where he is assistant to former Liverpool teammate Steven Gerrard.
Leeds, McAllister was a Liverpool Legends side beat AC Milan 3-2 in a charity match.
Rangers did not train on Monday owing to international break, McAllister was not expected to be at work.
Leeds CID quoting crime reference number 13190152147: Anyone who witnessed the attack in Leeds, or who has any information.