BRISBANE Lions midfielder Dayne Beams will undergo knee surgery next week and could miss the rest of the season.

Beams has struggled with knee tendinitis since the pre-season and only played his first game against Port Adelaide two weeks ago.

He copped a knock on the knee against Collingwood last Saturday night and will undergo surgery next Thursday.

"We're not sure of an end point, whether it's a month or the end of the season," Lions coach Justin Leppitsch said.

The injury is a complication from the tendinitis but has doctors confused.

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"His tendon looks OK, but there's still some pain in the area, so there's some unknown," Leppitsch said.

"That's been the frustration for Dayne, is that when you have an injury that even the medical profession is not sure about why there's bits of pain there and why the pain is so strong, that's where the frustration comes from.

"We'll get answers on that post-surgery."

It continues a wretched run for Beams, who had a shoulder reconstruction at the end of last season and missed the final five rounds.