Damon White will be out for four weeks after undergoing surgery on his knee on Tuesday.

The key forward injured the knee playing for North Adelaide on Saturday. He was initially diagnosed as being out for one to two weeks but when he had further pain on Monday night, he had MRI scans which revealed damage at the back of the kneecap.

White had surgery on Tuesday afternoon to repair the damage.

The club estimated him to be out for the next four weeks.

White had played every game this year until being dropped after the Round 12 win over Essendon.

White is the second player to have surgery this week after Danyle Pearce underwent an appendix operation on Monday. He'll miss two weeks.

The Power also lost back-up key forwards Ryan Willits and Adam Cockshell over the weekend through injury but neither should miss more than two weeks.