Michael Walker will start an eight meeting suspension after riding on Thursday in order to be back for the Cox Plate ride on equal favourite Criterion.

Walker was outed for careless riding aboard Fast `N' Rocking in the final race of the day on Wednesday.

Fast `N' Rocking raced to victory in the 1200m Listed sprint but stewards charged Walker with shifting in at the 150m mark when not clear of Dwayne Dunn's mount Kaepernick, causing crowding to Glen Boss on Moment Of Change and Craig Williams on Galaxy Pegasus.

Walker will have to relinquish his one ride on Saturday, the David Hayes and Tom Dabernig-trained Sacred Eye in the $500,000 Caulfield Classic, in order to be back in time for the Cox Plate on Saturday week.

"Michael Walker will take his suspension after tomorrow at Pakenham and return for Manikato night," Walker's manager Ryan Roberts posted on Twitter.

Sacred Eye, a stablemate of Criterion, is the Caulfield Classic favourite and one of the early Oaks favourites.

Walker won last Saturday's Group One Caulfield Stakes on Criterion and the horse is the $5 equal favourite for Saturday week's $3 million Cox Plate.