ESSENDON ruckman Tom Bellchambers will miss at least the next six weeks with a calf strain, but the club is hopeful he will return late in the season. 

The 29-year-old limped from the field in the third quarter of Thursday night's thrilling win over the Giants.

There were fears he had injured his Achilles tendon, but scans on Friday morning confirmed a calf strain.

FULL INJURY LIST Who's ruled out and who's a test?

Zac Clarke looms as Bellchambers' replacement.

The ex-Docker has only played three games for the Bombers since being signed on a one-year deal under the new pre-season supplementary period.

Bellchamber's injury isn't the only blow for the Bombers.

Defender Patrick Ambrose was a late withdrawal on Thursday night after sustaining a quad injury during the pre-game warm-up.

He will be sidelined for approximately three to four weeks.

Essendon football manager Dan Richardson said it was disappointing to lose the pair.

"Both Tom and Patrick had scans today, which confirmed the nature of their respective injuries," Richardson said. 

"We'll closely manage their rehabilitation programs, and we expect Patrick to return to the field in three to four weeks' time, while Tom will be pushing to return before the conclusion of the home-and-away season. 

"While disappointing, injuries presents opportunities for others to step up, so we are confident we have the depth to cover both Tom and Patrick over the coming weeks."