BRISBANE defender Dee Heslop has been banned for three games, the equal-longest AFLW suspension, in a crushing blow to the club's finals aspirations.

Geelong's Kate Darby will also miss her club's opening final after failing to overturn a one-match ban but Brisbane's Charlotte Mullins has been cleared of striking.

Heslop's only chance of playing again this season rests on Brisbane losing their qualifying final, then winning their next two games - she would then be available for the grand final.

Her three-game suspension equals the rough conduct sanction given to Adelaide's Najwa Allen this year.

Heslop was cited for rough conduct for a sling tackle that knocked out Melbourne ruck Rhi Watt in last Saturday night's clash.

Heslop's tackle was graded as careless conduct, severe impact and high contact and she was sent directly to the Tribunal.

Wednesday night's hearing was told Watt, on her head hitting the ground, was immediately unconscious. She has been ruled out of the Demons' elimination final against Geelong on Sunday and could miss the following week should Melbourne advance, the Tribunal heard.

The 22-year-old Heslop argued she didn't sling Watt in a tackle but had the entire weight of the Demon on her as they fell to ground.

"It was just an unfortunate event, her hitting her head," Heslop told the Tribunal.

"I have just gone to wrap her up, to make a tackle.

"I had no control, her momentum is falling back on me ... I had all her body weight on top of me."

The defender said she was unaware of Watt's injury at the time.

"I had no idea until I got told," she said.

"It's obviously not nice seeing someone get injured, especially coming into these rounds of finals."

The Tribunal upheld the charge, with Heslop to miss Brisbane's away qualifying final against Adelaide on Saturday and her club's two following matches.

Fellow Lion Mullins was cleared to play, overturning a one-match ban for striking Melbourne's Shelley Heath.

Mullins successfully had her charge downgraded from intentional to careless conduct, resulting an as-yet unspecified fine instead of a one-game suspension.

But Geelong's Darby will be sidelined from the Cats' elimination bout against Essendon on Sunday.

Darby was cited for rough conduct in a collision with Hawthorn's Jas Fleming last weekend but described contact as inevitable after the Hawk suddenly changed direction.

"The only thing that I could do when she did turn was brace my left side, knowing that we were going to make contact ... there was nothing else I could reasonably do," Darby said.

But the Tribunal found her guilty of the charge, rated as careless conduct, medium impact and high contact.