The Eagles have also confirmed they will launch the season without midfielders Daniel Kerr (knee), Sharrod Wellingham (ankle) and Matt Rosa, who has had thigh surgery.
Rosa pulled up sore after last Saturday's NAB Cup match against Port Adelaide and had surgery for compartment syndrome on Tuesday, which could rule him out for up to six weeks.
Naitanui, who had groin surgery in November, has made strong progress in recent weeks, but the Eagles have decided to delay his playing return until after the March 23 Derby.
“We were never going to rush him back into the team,” coach John Worsfold told westcoasteagles.com.au.
“It will be good to have him in our main training group this week after spending so long in rehab, and we will slowly build up his work load so that he has the appropriate level of conditioning to play when that time comes."
Kerr had a knee arthroscope in early December but his recovery has been complicated and there is no timeline for his return.
“Daniel has also been working hard but needs more time … when he is right to play, he will play," Worsfold said.
Andrew Embley will be available for round one after suffering a hamstring injury in the second round of the NAB Cup, while midfielder Chris Masten has been cleared of injury after missing last Saturday's clash against Port Adelaide.
Off-season recruits Jamie Cripps, Cale Morton and Mark Hutchings are all likely to press for round one selection in the midfield, while young ruckman Scott Lycett looms as Dean Cox's partner in the ruck against Fremantle.
"There is pressure on for places in the team and all available players are aware of that," Worsfold said.
"It is disappointing for those [injured] players, but it creates opportunities for others."
Nic Naitanui is a ruckman in NAB AFL Fantasy. He averaged 85.95 points in 2012. Register your team at our AFL Fantasy Hub .
Nathan Schmook is a reporter for AFL Media. Follow him on Twitter: @AFL_Nathan
