Collingwood is unsure of the seriousness of an ankle injury suffered by forward Paul Medhurst against North Melbourne on Friday night.

Medhurst disappeared up the race after initially hurting himself in the opening quarter but returned to play out the second quarter before again succumbing to the injury in the third term.

Malthouse praised Anthony Corrie and Sharrod Wellingham for their contributions after the pair replaced late withdrawals Heath Shaw and Anthony Rocca.

Corrie, playing in his first game since being traded from Brisbane, gathered 20 touches and kicked two goals, while Wellingham collected 23 disposals.

Both were 'very, very good', Malthouse said.

Malthouse said ruckman Josh Fraser, heavily criticised by former St Kilda coach Grant Thomas for 'dogging' a contest against Essendon on Anzac Day, played well despite being worn down late by North's big man pairing of David Hale and Hamish McIntosh.

"He has got a wonderful ability to clear the ball himself, I think that's one of his greatest assets," Malthouse said of Fraser, who had 25 possessions and 18 hitouts.

"He does play pretty close to the ground as a ruckman. The rest, the 10-day break couldn't come at a better time for him."

Malthouse praised the leadership of veterans Tarkyn Lockyer, Shane O'Bree and Simon Prestigiacomo, who have assumed senior roles in recent years following the departures of Nathan Buckley, James Clement, Paul Licuria, Shane Wakelin and Scott Burns.

"When you analyse the last two or three seasons we've lost a lot of wonderful players to retirement," he said.

"It was so important that players who are in that vintage step up and maintain that leadership."