Bonner sustained the injury in a collision before halftime in Sunday's thrilling two-point win over Gold Coast but was able to play out the game.
The 25-year-old was one of the Power's chief ball-winners with 30 disposals and has been in strong form.
But he will undergo surgery this week and faces a stint on the sidelines.
"(Bonner) is expected to miss three to four weeks of football as he recovers," the Power said in a statement.
In better news for Port Adelaide, Zak Butters is a good chance to return from a knee injury in Sunday's crunch clash with Fremantle at Optus Stadium.
Defensive duo Darcy Byrne-Jones and Tom Clurey will clear COVID-19 protocols and be in the frame to take on the Dockers.
Small forward Orazio Fantasia could also see his first AFL action of the year after overcoming separate knee and thigh injuries that have curtailed his output.
Fantasia was an unused substitute in round nine before hurting his thigh in a SANFL match.
He proved his fitness at the lower level last week, kicking 0.4 from 17 disposals.
Ruckman Scott Lycett will return to full training after corrective surgery on the shoulder he dislocated in round four.
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