Petrie, 34, will have surgery on Tuesday and could be sidelined for 10 weeks, Simpson revealed.

The North Melbourne recruit broke bones in his hand in an opening contact just a minute into his Eagles debut against his old club on Sunday in a spoiling attempt on former teammate Luke McDonald.

The new Eagles ruckman-forward then sprinted straight from Etihad Stadium for urgent pain-killing injections and running medical repairs to play out the game, which West Coast won by 43 points.

The 317-game veteran bravely contested marking, spoiling and ruck contests virtually one-handed as he protected his strapped and swollen left hand.

He will have plates inserted along the broken bones to assist rapid healing as well as secure the damaged areas in the back of his hand.

Petrie made his first Eagles appearance since crossing from the Roos last November as a shock rookie selection and was sharing ruck duties with another West Coast import Nathan Vardy.

Simpson disclosed during his weekly interview with Channel Seven on Monday night that his big import could be out for as long as 10 weeks.

"I haven't quite got the full results back yet but it is at the early stages, six to 10 weeks," he revealed.

"He will miss several weeks."

It is understood the best possible recovery rate for Petrie's return is only a month.

Simpson confirmed he will call up another recent ruck recruit Jonathan Giles to share the load with Vardy in Saturday night's first home engagement for 2017, against St Kilda.

Giles, 29, was hurriedly withdrawn from West Coast alignment outfit East Perth as confirmation of the severity of Petrie's injury spread through the Eagles camp during Sunday's opening term.

"We made the call as soon as we found out about Drew three minutes into the game," Simpson said.

"So we made the call from the (coach's) box to pull him out.

"We were aware that Drew was going to miss a few weeks.

"So we jumped on that opportunity and Gilesy will come in and he will play the role that we need him to play."

Simpson also revealed plans for a tighter defensive approach against the Saints after conceding 93 points to North, despite extensive scoring totals in the league's opening round.

"It's a week-to-week thing. We're definitely not satisfied conceding 93 points," he said. "We need to improve in that area."

The average winning score in the AFL's opening round was 119 points and 88 points for losing teams.

As new AFL football boss Simon Lethlean called for higher scoring right across the competition and new ruck rules and deliberate out-of-bounds regulations took effect, the winning side booted 100 points or more in eight of the nine opening round clashes.

Only Brisbane failed to top triple figures, holding off a fast-finishing Gold Coast to win 98-96.

West Coast's win was engineered through a seven-goal haul from ace full-forward Josh Kennedy and a stunning 38-possession first-up performance from champion import Sam Mitchell.

Simpson bluntly indicated he will continue with a running defensive brigade with two tall key backmen as well as all-rounder Elliot Yeo continuing as a creative and sweeping defender.

Yeo, 23, had 26 disposals and booted two handy goals in rivalling Kennedy and Mitchell as his side's best.

"I thought Elliot Yeo was one of our standouts as well, with what he did across half-back and how he managed to play out the four quarters," Simpson said.