A back complaint will see Essendon captain Dyson Heppell miss today's clash with Port Adelaide at Adelaide Oval.

The 28-year-old experienced back spasms late in Thursday's main session, and was given every chance to play after being named in the initial team.

He'll be monitored ahead of the Bombers' home game against St Kilda next week.

Martin Gleeson replaces Heppell in Essendon's line-up, while Zach Merrett will lead as stand-in skipper.

Tom Cutler has been named as the medical sub.

Essendon and Port Adelaide will battle it out from 4:35pm AEDT in round two action.

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