GEELONG ruckman Dawson Simpson has withdrawn from Sunday's top-of-the-table clash against Port Adelaide after rolling his ankle at training on Friday.

The 206cm giant failed to get through training on Saturday morning and has been replaced by 196cm forward Josh Walker in the undefeated Cats' team to take on the Power at Adelaide Oval.

Walker will play just his 11th career game and first for the season against Port Adelaide.

Midfield speedster Jesse Stringer has been added to Geelong's emergencies list for the game which kicks off at 4.10pm (ACST) on Sunday.

Twitter: @TravKing_AFL