When Geelong's dual premiership player Joel Selwood goes into battle in Saturday's AFL preliminary final, even his brothers and parents will be against him.

West Coast coach John Worsfold says he's planning to give Selwood's brothers, 21-year-old Scott and 27-year-old Adam, rotating shifts on Geelong's reigning club champion.

And Joel says his parents Maree and Bryce Selwood are placing their allegiances in the Eagles' camp because young Scott is yet to play in an AFL grand final.

Adam has already tried to get under Joel's skin with a text message which said: "We're just one day closer to smashing you on Saturday".

Joel, 23, is doing his best to keep his cool this week, on and off the field.

"No, I haven't sent one. I've spoken to him throughout the week, but he does write a bit of rubbish and talk a bit of rubbish sometimes," the Cats vice-captain said on Wednesday.

"I won't get into that."

Saturday's clash will be the first time three brothers have played in an AFL final on opposing teams.

Scott Selwood is in cracking form to take on Joel after his successful lockdown role on Carlton superstar Chris Judd in last weekend's semi-final win in Perth.

"I will cross him throughout the game, I'm sure," Joel said.

Scott was the leading tackler in the 2011 home-and-away season, so Joel knows what's coming his way.

But if Joel learnt any tricks from his childhood days in Bendigo on how to out-point Scott, he says he's forgotten all about it.

"It's a long time since I've been home and had a good wrestle with him," Joel said.

"But he is playing really good footy at the moment, they all are, and he's probably one that we've got to stop.

"He got some good centre clearances on the weekend when I was watching, and he's going well."

Joel said his parents were very proud of their boys, including Adam's twin Troy, an ex-Brisbane Lion now playing for Geelong's VFL side.

"To have three boys play prelim day, it's going to be exciting for them," Joel said.

"We're here because of them and they've brought us up the right way and we couldn't thank them enough."

Saturday's knockout clash will be a test of brotherly love in a game where victory brings a place in next week's grand final.

"I'm not sure if they're into all those sort of games," Worsfold said when asked if Adam and Scott would be poking Joel in the ribs behind the play.

"But it is a challenge I would expect, mentally, to play against your brother in opposing teams.

"They know their main focus. It's on playing the game and playing Geelong.

"We can go either way. So we'll start with one and maybe have to go to the other one."

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