PORT Adelaide key defender Jackson Trengove will undergo surgery on his injured foot on Monday and he is tipped to spend "an extended period of time" on the sidelines.

Trengove was subbed out of Saturday night's five-point win over West Coast at AAMI Stadium and while the club initially hoped his foot injury was minor, scans revealed a fracture requiring surgery.

The Power are unsure how long the 22-year-old leadership group member will be sidelined but he is expected to miss a considerable amount of football.

"After an incident in the game we thought it was only a minor foot issue, but given that he was unable to continue playing we had it investigated and found a metatarsal fracture," high performance manager Darren Burgess said.

"He’s having surgery today and we’ll have more clarity on length of time he’ll be out after that."

Harry Thring is a reporter for AFL Media. Follow him on Twitter: @AFL_Harry.