DAVID Zaharakis is in doubt for Essendon's Anzac Day clash against Collingwood with a knee injury.

Zaharakis had his right knee strapped when he arrived at AAMI Park to have scans on Monday morning.

The midfielder told reporters he was not sure whether he would be fit to play against Collingwood this Saturday.

Zaharakis suffered a minor medial strain to the same knee in February.

Earlier on Monday, Essendon spearhead Jake Carlisle also attended AAMI Park to have scans on his hip flexor.

Carlisle told reporters he expected to be cleared to play against Collingwood.