ESSENDON midfielder Dylan Shiel is unlikely to play again this season after his knee injury was worse than first feared. 

Shiel underwent an arthroscopy after suffering a torn meniscus in the round two loss to Port Adelaide. 

He was initially expected to miss 4-6 weeks, but the 28-year-old will now be sidelined for four months after he opted for more surgery to repair his damaged knee. 

“Dyl’ (Dylan Shiel) saw the surgeon early last week,” head of high performance Sean Murphy said on the club's website.

“The decision was made to go in for surgery for last Tuesday. In the end, the meniscal tear was quite significant, and the decision was made to repair the meniscal tear.

“What that means now is that there’s more of a lengthy period in terms of his rehab process and it’s looking like commonly a 16-week layoff to return to play.

“It’s big chunk of footy ‘Dyl’ is going to miss this year which is unfortunate for the club and for ‘Dyl’.”

MEDICAL ROOM The full AFL injury list

Defender Mason Redman remains in doubt for Thursday night's clash against Sydney after he was subbed out of last week's win over St Kilda with hamstring awareness. 

But in better news, skipper Dyson Heppell is a likely starter.

Heppell was a late withdrawal from the Bombers' round two loss to Port Adelaide with a back spasm and also missed Saturday's win over St Kilda.

"He's been improving all the time, he'll train today and if he gets through that fine, he'll be available for selection," coach Ben Rutten told reporters on Tuesday.

"If he plays, he'll play AFL."