JAKE Stringer has been ruled out of Essendon's round one clash against Hawthorn due to a hamstring injury.
The forward suffered the injury ahead of the Bombers' match simulation against Gold Coast last month and missed both of his side's pre-season hitouts.
PLAY AFL FANTASY Pick your team NOW
Stringer, 28, will also be sidelined for his side's season-opener against arch-rivals the Hawks at the MCG on Sunday as he builds up his training loads.
"Our performance team have put together a comprehensive plan with Jake to get him back to his best post injury. He participated in a strong session on Saturday, and we want to make sure he has block of full training with the main group before he is available for selection," Essendon general manager of performance Daniel McPherson said.
"It's a long season ahead and we want to ensure Jake is fully ready to go when he returns to play, so we won't be rushing him back."
Forward Matt Guelfi (calf) and Kyle Langford (back) are in the frame for selection after playing in a VFL practice match on Saturday.
Former captain Dyson Heppell (foot) is no certainty to face the Hawks, while second-year midfielder Ben Hobbs (calf) will resume full training this week.
Jye Caldwell is also joining the main group this week after suffering an ankle injury in the Bombers' practice match loss to St Kilda.
"Jye suffered a minor sprained ankle against St Kilda. He's been really diligent with his rehabilitation which has enabled him to return to running in a short amount of time," McPherson said.
"He has satisfied all the milestones set by the high performance team and will reintegrate into the main group this week."
Nik Cox (back), Zach Reid (back) and James Stewart (foot) are weeks away from returning to full training, while No.5 draft pick Elijah Tsatas is out for three to four months following knee surgery.