JUSTIN Leppitsch is happy with the fitness of Josh Green and Allen Christensen, despite club legend Jason Akermanis claiming that the pair are overweight.

But the Brisbane Lions coach hopes the comments of his former teammate steel Green and Christensen for big performances against Carlton on Sunday.

Akermanis told AFL.com.au earlier this week he thought the small forwards "don't look physically fit enough" and it was taking away from their ability to create pressure and tackle.

But on Thursday, Leppitsch went into bat for the duo. He said Christensen had steadily improved his fitness following off-season back surgery.

"It's disappointing. I don't know how Jason would have looked in the white jumper a few years go. He wasn't always a striking picture himself," Leppitsch said with a little smirk.

"Allen knows he's on a slow cycle back. He's been dropping weight every week for three months now. He's very conscious of it. He's in good shape.

"He's not a naturally muscular type. Those comments don't help that's for sure, but maybe it will steel those two boys."

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Leppitsch said like Christensen, Green was a "big, sold boy" who had put on muscle in recent months.

"You see lots of players in the competition that aren't ripped to the hilt," he said.

"Our captain (Tom Rockliff) himself isn't ripped, he doesn't have a six-pack. Some players naturally can get it. I couldn't when I was a player.

"Hopefully it inspires the boys to perform well.

"(It's) not overly accurate. We've got their markers and we're happy with where they're at."

Leppitsch was critical of his small forwards following last Saturday's 64-point loss to Gold Coast, saying their inability to keep the ball inside the forward 50 was hurting the Lions.