THE LONG-TERM injuries to Steele Sidebottom and Levi Greenwood will test Collingwood's midfield depth like never before, coach Nathan Buckley concedes.

Sidebottom is due to have an operation on his broken thumb later on Tuesday, sidelining him for up to two months, while Greenwood is looking at the same time out with a hairline fracture of his ankle, suffered in the final NAB Challenge game on March 21.

The Magpies will confront Adelaide at Etihad Stadium on Saturday afternoon, the Crows fresh off a 77-point annihilation of North Melbourne at Adelaide Oval.

"We've got two of our first-choice midfielders who won't play for a period of time so it's a challenge for us," Buckley said on Tuesday.

"We believe in our midfield depth, and the players that we can run through there are actually a strong point, and that will be tested.

"We'll be looking to introduce fresh legs through there, whether that be forwards who play more midfield time or whether we bring some young players into the mix that have been thereabouts in the VFL."

Buckley named Sam Dwyer, Tim Broomhead and Paul Seedsman as those in the running to replace Sidebottom, while he also singled out Darcy Moore and Jonathon Marsh for their efforts in defence for the Magpies' VFL team in a practice match against Casey Scorpions on Saturday afternoon.

Buckley will have noted that the Crows' dominance against North was borne out of their midfielders' ability to win the ball in tight, smashing the Kangaroos in contested possessions (142-115), and allowing star forward Taylor Walker to take full toll with six goals.

"He moves really well. He just looks like a big midfielder," Buckley said of Walker.

"He's got great agility. He's got an understanding of the game and where to put himself and he can impact aerially.

"Their forwards are all dangerous – (Eddie) Betts, (Taylor) Walker, (Tom) Lynch, (Josh) Jenkins, (Charlie) Cameron.

"They've got quite a few scoring avenues."

In positive news for the Magpies, Ben Reid will play in the VFL this weekend as he builds his way back up from a series of soft-tissue injuries which limited his pre-season.

"Ben will play this week and continue to increase his game load," Buckley said.

"We think we're managing him really well. Externally, there's an impatience to see him up and about.

"But we've said all along that ‘Reidy’ will play when he's ready, and he's still got some more game load to get in.

Buckley wouldn’t be drawn on the situations of Lachlan Keeffe and Josh Thomas after the pair returned a positive A-sample test to the performance-enhancing drug clenbuterol.

"There won't be any change in their status until the 'B' sample gets tested (on April 14)," Buckley said.