Carlton defender Jeremy Laidler will have surgery and is out of AFL action for up to six weeks because of his dislocated kneecap.

The Blues announced that Laidler would undergo an arthroscopy on Tuesday afternoon after suffering the gruesome injury during Sunday’s pre-season game against the Western Bulldogs.

Laidler met with a specialist and Carlton medical staff on Monday night.

He fell awkwardly during a marking contest in the first quarter of the game at Etihad Stadium.

Laidler’s left kneecap was bulging to the lateral side as he battled severe pain, with fans gasping in horror at the replays on the video scoreboard.

Coach Brett Ratten said the Blues were able to put the kneecap back in place before Laidler was taken to hospital during Sunday’s game.

Blues team-mate Ed Curnow said Laidler was a key member of Carlton’s defence.

“He’s shattered,” Curnow said.

Curnow said he had been running around in midfield when Laidler was injured.

“I did have a quick look on the big screen and I got grossed out a bit myself,” Curnow said.

“I’m sure he’s going to bounce back.

“We’ve got a lot of guys who can play that role, down back, that I’m sure will step up.”

The Blues expect to regain forwards Jarrad Waite and Andrew Walker, onballers Chris Judd and Mitch Robinson and defender Nick Duigan for Saturday’s round-three pre-season cup game against Brisbane at Maroochydore.

Carlton’s best defender Michael Jamison trained at Visy Park on Monday morning and is on track to overcome a back injury in time to play in round one against Richmond at the MCG on March 29, Curnow said.

The Blues are chasing a spot in the top four in 2012 after finishing strongly in fifth place last season following a heartbreaking three-point semi-final loss to West Coast in Perth.

The Blues have lost all three of their pre-season cup games by single-figure margins and Curnow says experimenting with positional changes is a key factor at this stage of the year.

“We’ll probably want to go into the season with a bit of winning form,” he said.

“But we also want to try out guys in different positions, send Shaun Hampson up forward for a bit longer than he usually would play, little things like that.”