ESSENDON'S No.1 ruck role is suddenly up for grabs after Tom Bellchambers underwent knee surgery last week, compounding the Bombers' summer of injury woes.

The 30-year-old is recovering after going under the knife for a procedure that is expected to keep him sidelined from running for the next fortnight.

After completing most of the pre-season to date, the Bombers are hopeful the setback won't cause too much disruption to his preparations for 2020.

However, it has opened the door for recruit Andrew Phillips to bolt into contention for the season opener against Fremantle on March 21.

The 28-year-old signed a one-year deal at Tullamarine in search of greater opportunity after 27 games in four seasons at Carlton. 

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Phillips has impressed since crossing from Ikon Park in October and is expected to lead the Bombers' ruck division in the bulk of pre-season matches starting next week.

The Bombers begin their campaign with a hitout against Melbourne (February 21) before Marsh Community Series matches against West Coast (February 27) and Geelong (March 9).

Untried ruckman Sam Draper, who last year signed a four-year extension while recovering from a ruptured ACL he suffered in May, is expected to join full training in coming weeks. 

The Bombers also added 202cm Oakleigh Chargers ruckman Nick Bryan in last year's NAB AFL Draft as a long-term prospect.

The shortage of ruckmen has forced the Bombers into a late addition to its trialists for the club's last available rookie berth.

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East Fremantle beanpole Brynn Teakle (202cm) was flown in last week as the Bombers weigh up a replacement in the pre-season supplemental selection period (SSP).

The 20-year-old has joined Nigel Lockyer and Nathan Ireland as candidates to take the vacant position left open by draftee Lachie Johnson's ACL.

Bellchambers' latest setback comes after a torrid time of injuries at Essendon this summer.

Captain Dyson Heppell continues to recover from a foot injury, while Joe Daniher (groin) appears set to miss a bulk of the first half of the season. 

Cale Hooker (knee), James Stewart, Noah Gown (foot) and Mitch Hibberd (knee) are also part of the current rehab group.

Michael Hurley (shoulder), Orazio Fantasia (hip/knee), Dylan Shiel (knee) and David Zaharakis (ankle) are back in full training after delayed starts to pre-season.