THE SISTER of Collingwood star Travis Varcoe has died four days after she sustained a head injury during a football game.

She was admitted to hospital on Sunday after she accidentally clashed heads with a teammate while playing for Angle Vale Football Club in an Adelaide Football League women's grand final.

She reportedly walked off the ground after the on-field collision but collapsed in the changerooms and was in a coma at the Royal Adelaide Hospital before dying on Thursday.

Travis Varcoe returned to Melbourne to address his teammates on Tuesday before flying back to Adelaide late on Wednesday to keep vigil by Maggie's bedside.

News of her death was confirmed in a Facebook post by Angle Vale on Thursday evening.

"You were a much loved member of our women's team who all idolised you both on and off the field," it read.

"Your infectious smile and kind nature will be truly missed around the club you chose to call home. We will do whatever we can to support the Varcoe family and the AVFC family who are all deeply saddened by this tragedy."

A year to the day I lost my brother, I hear the sad story of Trav Varcoe’s sister!! The situation feels to similar. Sending love and prayers to Trav and Family. The industry will wrap their arms around his family now ❤️ — Sam Jacobs (@samjacobs24) August 30, 2018

Adelaide Football League CEO John Kernahan told The Advertiser that he was shocked by the news.

"Like everyone in the football community, we are devastated at the tragic loss ... ," Kernahan told the newspaper.

"[She] received the best medical attention, both at the ground and at the Royal Adelaide Hospital and our thanks go to all the medical professionals who did so much for her.

"We have been in constant contact with the Angle Vale Football Club and our thoughts and deepest condolences go out to the Varcoe family, ... friends and teammates. She was a talented, spirited and passionate young woman who absolutely loved her footy.

"I know I speak for the entire football community when I say that she was very much loved in return."

In a statement, Collingwood extended its sympathies to the Varcoe family.

"The thoughts and love of all at the club are with Travis in this most difficult time.

"Collingwood will continue to support Travis and his family in any way it can and allow him as much time as he, and they, require to decide upon a return to the club. We ask that the privacy of the Varcoe family be respected."

Varcoe and brother Adam's former club Geelong also released a statement.

"With both Travis and Adam Varcoe being past players of Geelong, the family has a long association with the club. At this terribly sad time we offer our support and condolences to the family and all those who knew and loved Margaret," the statement read.