Powell-Pepper collected Keane's head with a hip-and-shoulder bump in the first quarter of the drawn trial game at Alberton Oval on Friday evening.
The Power star kicked two goals and scores were tied 14.9 (93) apiece after four quarters.
The first-term flashpoint came as Keane had possession and was caught in a Willie Rioli tackle that swung the Crow as Powell-Pepper charged in.
Powell-Pepper's right shoulder struck Keane on the right side of his head.
Keane slumped to the ground as Crows staff rushed to his aid, with the Irish-born backman soon helped from the field by two medicos.
Powell-Pepper, added to the Power's leadership group for the looming season, will be scrutinised by the AFL's match review officer.
And although Port have another trial game next weekend, any suspension to Powell-Pepper would be served in the premiership season.
The Power's campaign opens with a home match against West Coast on March 17.
"We know the way Pep plays, he's hard and tough, but I can't comment on the actual contest," Port assistant coach Chad Cornes said.
The incident is also another blow to Adelaide's depleted stocks of tall defenders, with Keane placed under AFL concussion protocols for the next 12 days.
There was some suggestion of Keane suffering a broken jaw but Adelaide assistant coach Scott Burns was awaiting information post-game.Â
"Honestly, I haven't seen him or checked with the doctors so I can't really answer that," Burns said.
Keane had been earmarked to fill a void left by sidelined big backmen Nick Murray (knee reconstruction) and Jordon Butts (foot).
Murray won't be fit until mid-season while fullback Butts, who suffered a foot injury last July which ended his 2023 season, suffered a hamstring injury three weeks ago.
The off-season departure of versatile Tom Doedee to Brisbane has also thinned Adelaide's taller options in defence.
Keane's injury pushed the Crows into an early unveiling of prized draftee Daniel Curtin in a tall defensive slot in a free-flowing trial game before a 5,211-strong crowd at Port's Alberton base.
Adelaide's vaunted attack, the highest scoring in the league last season in the home-and-away rounds, again threatened.
Crow Ned McHenry kicked three goals and teammates Riley Thilthorpe, Darcy Fogarty, Izak Rankine, Josh Rachele and Ben Keays finished with two each.
Port's Rioli, Darcy Byrne-Jones and Ryan Burton, rebounding from halfback, joined Powell-Pepper with two goals apiece.
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