ESSENDON coach Mark Thompson is puzzled by Jake Carlisle's hamstring injury and has suggested the key forward could have been playing this weekend.

The finals-bound Bombers have ruled Carlisle out for Saturday's last-round clash with Carlton at the MCG.

Carlisle spoke this week about how he expected his tight hamstring would only put him out for one or two matches.

"I don't know. I've never heard of a one-week hamstring injury," Thompson told reporters on Friday.

"He probably more than likely won't play (next week).

"They're saying it's not very big. It's only a few fibres and it should be right.

"But if that was the case he'd be playing this week.

"You've just got to get off the fence don't you and decide if it's a hamstring or not.

"If it is it's two weeks and if it's not you should be playing this week and have a crack at it."

Essendon have recalled ruck/forward Tom Bellchambers to assist No.1 ruckman Patrick Ryder.

Thompson says if Bellchambers can find form against the Blues, he'll be retained for next week's elimination final.

Bellchambers has played six senior games this season.

Listed at 108kg, Bellchambers has lost weight and been doing lots of cross-training.

"He's had a cow of a season. He has been absolutely destroyed by the pre-season injury to his ankle," Thompson said.

"If he doesn't play well, unfortunately we won't go with him.

"We're hoping that it does work. It was our most preferred set-up at the start of the year."

Essendon have also recalled gun utility Dyson Heppell after one week out with a broken hand.

"We're not in that position where we can flirt with anything. We need to win," Thompson said.

"We need to go into the first final in good form."

Port Adelaide thrashed Carlton by 103 points in last week's round-22 game and coach Mick Malthouse said his Carlton side were tired.

"It's amazing what can happen in a week. I've seen it all before," Thompson said.

"I hope he's not trying to psyche our players out because it's not going to happen.

"We know the cue is not in the rack for them. We know he's trying to motivate them by saying they're tired.

"They'll come out and they'll try to really attack us. We know that's coming."