The reigning best-and-fairest winner, who turned 26 on Monday, consulted a specialist the same day and was told that he needs an operation to fix an injury suffered in the round-eight loss to Sydney.

Smith has also managed a pre-existing posterior cruciate ligament problem in the same knee for the past two years and the club has decided to have that fixed at the same time.

Addressing the fresh injury, to the trochlear beneath his kneecap, on its own would likely have allowed Smith to return this season, but having both done will require up to six months of rehabilitation.

"There's Devon's long-term health beyond football, there's his long-term football career that's taken into account, and those two things are a bigger priority than the immediate ... there's no doubt about that," coach John Worsfold told reporters on Tuesday before the final decision had been made public.

"He's very disappointed that he's not going to be playing footy for the remainder of this year, and we're disappointed for him.

"But we're really keen that he gets his knee fixed so that he can play good footy for a lot longer."

The loss of the hard-tackling forward is another blow for an AFL attack that has struggled find rhythm due to injury this season.

But it's not all doom and gloom for the 10th-placed Bombers, who scrapped to a much-needed win over Fremantle last week, to improve to a 4-5 record.

After long stints on the sidelines, tall forwards Shaun McKernan (hamstring) and Mitch Brown (fractured wrist) are in the selection mix for Saturday night's annual Dreamtime at the 'G clash with Richmond at the MCG.

Defender Marty Gleeson won't be considered for AFL selection, but he has been cleared for a return, most likely with limited minutes, in the VFL.

Gleeson's last AFL appearance was in an elimination final loss to Sydney in 2017.

A major ankle injury ruined his 2018 season before a pre-season cheekbone fracture delayed his start to the 2019 campaign.

"He's back this week and he's pretty excited about it," Worsfold said.

"The injury he had with that little fracture, he just had to avoid any accidental knocks so he hasn't been able to join in training, but he's been able to run and do full workloads.

"It won't take him long to be putting his hand up for (AFL selection)."

Australian Associated Press