REINING in Adelaide's dangerous defenders will be a key focus for St Kilda when it attempts to topple the Crows on Friday night at Adelaide Oval, forward Mav Weller says.

Adelaide has not dipped lower than second spot on the ladder this season, and part of the reason for that is because of their exceptional ball movement, which often starts from the backline.

Weller has done his preparation on the players who are an important part of Adelaide's scoring chains, and knows he will have to take his aggressive tackling to South Australia.

"We have to be on our toes with some of their movers – Rory Laird, Brodie Smith, they're crucial to their ball movement, and we'll have to be conscious of that," Weller told AFL.com.au.

Forward-line tackling is a facet the Saints always want to get right, but Weller pointed out it would take more than that to stop the Crows' rebounding runners.

"A step before that's getting the right match-ups and staying relevant to those," he said.

"There's some quality players that can read the ball. Jake Lever's in pretty good form and I think they're working really well as a backline.

"We'll get the right match-ups, we'll get our structure how we want it, and we'll play footy from there."

Lever was No.1 in the AFL for intercept possessions (10 per game) and intercept marks (four per game) going into round 12.

Weller, 25, started his career at Gold Coast but was delisted at the end of 2013.

He was snapped up by the Saints just under three months later in the rookie draft and has flourished, cementing a spot in their best team and becoming a member of the leadership group.

The Tasmanian lines up in his 100th game this week.

"It's probably one of those things you reflect on after it's all done, but the other day my old man texted me and said congratulations. It's a good achievement and it's something that's very humbling," Weller said.

His younger brother Lachie is showing exciting form for Fremantle and although the Docker is signed at the club until the end of 2018, Mav is holding out hope the pair can play together.

"It would be a dream come true, it would great. Just like old times in the backyard," Weller said.

"A lot of water's got to go under the bridge for that to happen. He's going really well.

"The family's super-proud of him, and you never know what's going to happen."