RICHMOND and Essendon have made late changes to their sides ahead of tonight's Dreamtime at the 'G clash.

Key Tigers defender Graham Polak has been replaced by lively half-forward Kayne Pettifer, while Essendon has given utility player Jay Nash the call-up to replace midfielder Ricky Dyson.

Reports on Triple M suggested Dyson has fallen ill, possibly with appendicitis.

A large crowd is building for the awaited match, with bouncedown at 7:45pm AEST.