Former Geelong footballer Paul Brown has suffered bleeding on the brain and a fractured skull after allegedly being king hit in Shepparton.

The 46-year-old former player was allegedly punched by another man after rushing to the aid of a young woman in distress outside a Vaughan Street shop about 9.15pm on Friday.

The woman was allegedly involved in an altercation with a man outside the shop. But her attacker allegedly turned on Brown after he intervened. 

Brown, a dual grand final player with the Cats, was allegedly king hit by the man and knocked backwards, hitting his head on the concrete pavement.

The 19-year-old Shepparton man was arrested shortly after the incident. He was bailed to face Shepparton Magistrates Court on January 11.

Brown was taken to Goulburn Valley Hospital, but was later rushed to The Alfred hospital after his condition worsened at the weekend.

He was in a serious but stable condition at The Alfred, where his family and friends have maintained a bedside vigil, on Monday morning.

Brown, originally from from Echuca, played 84 games for Geelong, including the 1994 and 1995 grand finals