Blake Shinn will undergo a full medical assessment before he can return to race riding after ruling himself out of Saturday's Magic Millions meeting.

Shinn needed attention from ambulance officers in the stewards' room at Gosford on Thursday soon after winning the Belle Of The Turf Stakes on Cathay Lady.

The jockey was stood down from his remaining rides and also from Friday night's Canterbury meeting pending the result of a medical assessment.

But on Friday Shinn ruled himself out of action for the night meeting and the Magic Millions day on the Gold Coast.

He was booked to ride leading Magic Millions Guineas contender No Looking Back.

"Blake Shinn advised stewards that he intends to undergo a full medical assessment prior to resuming race riding," a Racing NSW statement said.

Glyn Schofield will ride No Looking Back.

"Not riding tomorrow because I need to be satisfied that I'm in good enough shape to ride. It's pretty shattering but my health is paramount," Shinn tweeted.