The Brisbane Lions have been issued a gentle reminder from Chris Fagan after the coach noticed a "trend" that's punched a hole in their usually water-tight AFL defence.

The premiers travel to Marvel Stadium to face St Kilda on Saturday with a 5-1 record and, on the surface, in terrific shape.

But Fagan wasn't impressed with what he saw at the Gabba last Thursday in a blowout loss to Collingwood.

They conceded 105 points after letting in 97 and 90 in victories in the previous two games.

The 97-point average spanning those three weeks is a huge outlier to the 76 conceded on average during their 2024 campaign.

"Reflected a lot on it, mainly because the last three weeks we have been poor defensively," Fagan said on Thursday of the Magpies loss.

"Team defence has been a huge focus this week; I feel like that's dropped away and it's the first thing that drops away when either attitude or energy's not right."

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

Team defence is a catch-all term that includes off-the-ball running, effort to locate opponents, contested work and tackles.

"There's a lot of elements to it ... we watch that more than we watch anything else," Fagan said.

"I don't think it's attitude, it's something we're monitoring.

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

The coach also shot down suggestions that the club had spoken to Jamarra Ugle-Hagan about a move from the Bulldogs, where his future remains unclear.

"I think people speculate on those sorts of things," Fagan said.

"They go, 'Oh, Joey Daniher left, the Lions are in the market for a tall forward'.

"I don't know anyone at our club that's spoken to Jamarra and his management.

"Sometimes in the past we've seen players move from one state to another state and it's been good for them, but I don't really know his story."

The coach also revealed Adelaide recruit Tom Doedee, who has played two VFL games since returning from a third knee reconstruction, was yet to declare himself ready for an AFL return.

"He's not at that point yet ... two years out of the game, trying to build his confidence in his body," Fagan said of the defender, whose last AFL game was in June 2023.

"Once he gets some continuity he'll come and tell me when he's ready."

Even then it won't be a walk-up start for the former Crow, with Harris Andrews, Jack Payne and Ryan Lester locking down the key defensive posts.

"I reckon last year he would have been but it's two years since he played," Fagan said.

The coach also said fellow defender Keidean Coleman, who tore his anterior cruciate ligament in the first round of last season, would likely return in the VFL next week.