CHRIS Fagan won't consider playing Tom Doedee at senior level until the former Adelaide defender comes knocking on his door.

Doedee is currently on the comeback trail from his third knee reconstruction and will run out for his third VFL game of 2025 against Sandringham on Saturday.

Brisbane's coach said he would be guided by the 28-year-old on the path forward.

"Once he gets some continuity, he'll come and tell me when he thinks he's ready to put his hand up for senior selection and I'll just go with his feel for it," Fagan said on Thursday morning.

"I think it's quite a unique situation that he finds himself in.

"He's been two years out of the game and he's trying to build his confidence back in his body. He feels like he's getting better each time he goes out there."

When Doedee arrived at the Lions via free agency late in 2023, he was midway through rehabilitation from his second ruptured anterior cruciate ligament.

Following one game at the lower level early last season, Doedee was ready to play his first game in Brisbane colours on Easter Thursday before re-tearing the same ligament in a training session.

He hasn't played an AFL game since June 3, 2023, when he turned out for the Crows against Gold Coast in Darwin.

With co-captain Harris Andrews, in-form Jack Payne and reliable Ryan Lester holding down the key defensive posts, Fagan said there was no easy path into the top team for Doedee.

"It's not easy. He's just got to play well and knock the door down and wait for an opportunity, whether that be form or injury. That's the way we see it," he said.

"It's two years now since he's played.

"We've got to give him the best chance to be at his best when he does come in. It could be a challenging conversation at selection."

With the Lions coming off their first loss of the season against Collingwood, Fagan said there was a renewed focus on defence this week ahead of tackling St Kilda at Marvel Stadium on Saturday.

"The last three weeks we have been poor defensively," he said.

"Even though the win again the Dogs was a ripper and the win against Richmond was solid enough, we still conceded way too many points compared to where we were the first three weeks of the year and where we were at for most of last year.

"Team defence has been a huge focus this week.

"I just feel like that's dropped away, and it's the first thing that drops away when either attitude and energy is not right.

"I've seen a trend, so we've talked about that this week.

"It's one of those things you've just got to give your group a reminder about every now and then.

"I think every team goes through it and we've gone through it the last three weeks."

Kai Lohmann is expected to be named to play after missing the past three matches with an ankle injury.