Rankine and club officials will meet with the AFL's integrity unit on Monday after the star Crow allegedly made a homophobic comment to a Collingwood opponent.
If found guilty, Rankine could be suspended for ladder-leader Adelaide's looming finals campaign.
The AFL has previously handed suspensions ranging from three to five games to players guilty of homophobic slurs.
The top-placed Crows have one home-and-away game remaining and are assured of hosting two finals.
"It's not ideal but it's obviously in the AFL's hands and we will let them investigate and see what happens," Adelaide captain Jordan Dawson told reporters on Monday.
"We will wait and see but we will leave it up to the AFL to go through what they have to go through."
Rankine was unsighted at Adelaide's West Lakes headquarters on Monday as a club spokesman said the club was in discussions with the AFL's integrity unit.
The AFL confirmed an investigation but didn't name Rankine despite the 25-year-old known to be the player involved.
"The AFL is aware of an alleged matter, with the AFL integrity unit making enquiries," the league said in a statement.
The AFL this year banned West Coast's Jack Graham for four games after he admitted a homophobic slur against a GWS opponent in round 17.
Last year, Gold Coast's Wil Powell was suspended for five matches and Port Adelaide's Jeremy Finlayson was banned three games, both for making homophobic comments to opponents.
Any ban for Rankine, renowned as among the league's most talented players, would be a hammer blow to the Crows' finals campaign.
Adelaide leadership group member Darcy Fogarty said AFL players were well-educated about homophobia.
"We definitely get enough (education)," Fogarty told reporters.
Fogarty refused to detail whether Adelaide's leaders had met with Rankine.
The Crows, who defeated Collingwood by three points on Saturday night, will enter the finals in top spot if they defeat lowly North Melbourne this weekend.
Adelaide will then host two finals in the club's return to the playoffs for the first time since losing the 2017 grand final.
Rankine is yet to play a final. He spent three seasons with Gold Coast before the Adelaide-born playmaker joined the Crows at the end of the 2022 season.
Last Monday, Rankine spoke of his excitement at Adelaide's finals campaign.
"I have never been this high on the ladder before so it's quite nice," he told reporters.
"We'll appreciate it ... it's nice to think about, but we know we have some more steps to take throughout the year."
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