Jockey Michael Walker will miss the rest of the Sydney autumn carnival including the Queen Elizabeth Stakes ride on Criterion because of a possible head injury.

Walker's manager Ryan Roberts said the jockey had an accident at home on the weekend, and initial scans of his head were inconclusive.

The jockey will be assessed by Racing Victoria doctor Gary Zimmerman on Tuesday.

"He had an accident over the weekend and he had some scans which were a bit inconclusive," Roberts said.

"So he's got to go and see Dr Zimmerman tomorrow, the Racing Victoria doctor, because of his history in the past when he had his hunting accident.

"He won't be riding for the next couple of weeks at least."

Walker suffered serious head injuries in a fall down a cliff while pig hunting in New Zealand in 2008.

Criterion will be aiming to win the Queen Elizabeth Stakes for the second straight year on Saturday in what will be his final start before he is retired to stud.

Walker has ridden Criterion to a Group One win in the Caulfield Stakes last spring and was also aboard when the horse was second in the Cox Plate and third in the Melbourne Cup.

He rode Criterion to third in the Ranvet Stakes at Rosehill last month.