COLLINGWOOD's ruck crisis has deepened with confirmation big man Dan McStay will miss a lengthy period after undergoing surgery on a damaged finger this week.

McStay hurt the finger early in the Gather Round clash against St Kilda and was subbed out during the first quarter.

Scans showed the flexor tendon injury was a complete rupture requiring surgery, meaning the former Lion will be unable to participate in ball work for six weeks while he recovers.

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On Wednesday captain Darcy Moore backed Nathan Kreuger to help solve the Magpies' ruck problems as they prepare for the Anzac Day blockbuster against Essendon.

Pies coach Craig McRae has had to get creative during the early stages of the season with Darcy Cameron, Mason Cox, Aiden Begg and Dan McStay all unavailable through injury.

Regular defender Billy Frampton was used in the lead ruck role during last week's win over St Kilda and Ash Johnson provided some support.

Kreuger's imminent return could provide some relief.

The 23-year-old underwent a right shoulder reconstruction in January and has not played a senior game this season, but returned to action in the VFL last week.

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Kreuger was spotted palming ruck taps to McRae during Wednesday's training session.

Moore declared the versatile ex-Geelong tall ready to play in what would be his eighth senior game in the second-versus-third clash with Essendon at the MCG, where about 90,000 fans are expected to be on hand.

"He's certainly in a position to come in," Moore said on Wednesday.

"He's spent a few months in rehab with his shoulder injury so it always takes a little bit of time to get match practice, but he's a super-competitive player and he played like it on the weekend at VFL level.

"He's definitely someone who won't care what position he's in. If he's asked to come in and play in the ruck, he'll come in and do his job for sure."

In comparison to their rivals, Essendon's tall stocks are relatively healthy despite leading goal-kicker and part-time ruckman Peter Wright being sidelined with a shoulder injury.

Sam Draper and Andrew Phillips have formed a strong ruck partnership under new coach Brad Scott this season and were crucial in the Bombers' upset win over Melbourne last week.

"The way they've worked in synergy and freed each other up to go forward and get on the scoreboard has been massive for us," Essendon vice-captain Andrew McGrath said.

"They've given us another option up forward and it really helps with our small forwards with bringing the ball to ground.

"They rarely get out-marked and their competitiveness, both of them, and their willingness to do anything for the team has been a standout.

"They were two of our best on the weekend and we're hoping they have another really good game against the Pies."