West Coast youngster Dom Sheed will miss nearly half the AFL season with a torn pectoral muscle.
Last year's grand finalists will also be without Sharrod Wellingham for possibly a month as he struggles to overcome a knee injury.
The Eagles announced that Sheed was undergoing surgery on Monday night after suffering the injury over the weekend.
The 20-year-old midfielder had missed West Coast's three pre-season matches because of knee surgery.
He returned in East Perth's local season opener on Saturday, but was hurt during the match.
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West Coast expect him to be sidelined for about 10 weeks.
Sheed had a breakout second season in the AFL last year, finishing third in the Rising Star.
Wellingham hurt his knee in an intraclub match about a month ago and it has been slow to heal.
The Eagles said he is improving, but have ruled him out for three or four weeks while he regains fitness.
West Coast are also without Chris Masten (ankle) for the start of the season and Lewis Jetta (calf) is in doubt for Sunday's round-one game against Brisbane.
