COLLINGWOOD is treating the events of this week as a watershed moment and how it responds will help determine the course of its 2015 season, defender Alan Toovey says.

The whole club was thrown into a state of shock following the news Lachlan Keeffe and Josh Thomas had been provisionally suspended after they both returned a positive A-sample test to performance-enhancing drug clenbuterol.

With the Magpies travelling to Brisbane to take on the Brisbane Lions at the Gabba on Saturday night, Toovey said the club has to respond in positive fashion.

"When things like this happen, you can go into your shell and everyone can split up or you can come together and become even closer," Toovey told afl.com.au.

"It's a good chance for the group to show how united we are.

"If we're going to do it alone, it's going to make it a lot harder.

"Coming together is the only option we have really."

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Toovey said the Collingwood players were stunned when they first heard about Keeffe and Thomas' positive tests.

He said their job was to continue to support the pair as they deal with the serious situation.

"A couple of boys have caught up with them," Toovey said.

"Everyone was very, very surprised and shocked at what had happened and confused about how it could happen."

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Now an 'elder statesman' in Collingwood's youthful backline, 28-year-old Toovey believes he'll need to take more ownership and be more vocal in directing the likes of Tom Langdon, Ben Sinclair and Marley Williams.

"We've got a young backline now so I think my role will step up again and hopefully I can make sure the boys are doing the right thing and getting in the right spots," Toovey said.

"Myself and Nathan Brown will have to take on a bit more of a leadership role."

The return of Brown, who played just three games in 2014 because of a season-ending shoulder reconstruction, is critical for how the Magpies contain opposition scores this season.

With Ben Reid still under an injury cloud, and not due back until the club is confident he is fully fit, Brown and Jack Frost are set to be assigned the best opposition key forwards.

"To have an experienced defender and a big guy with a lot of strength is really important. He's always sitting back and directing traffic from behind," Toovey said.

"He's got that advantage of using his voice really well so he's going to be an important part of our year."