Update - Michael Walker's agent Ryan Roberts reported later on Saturday that Walker was out of hospital after receiving fluids. Roberts said that Walker was struck down with severe dehydration after wasting to ride at 53kg.
Earlier report - Group 1 winning jockey Michael Walker was taken to hospital in Brisbane moments after winning the Group 2 Queensland Guineas (1600m) on the Chris Waller trained Sambro at Doomben on Saturday.
Walker was assisted back to the jockey's room after obviously not appearing to be well as he pulled Sambro up after the win.
He was replaced on all rides later in the programme.
Walker has been in good form with Waller over the Queensland Winter Carnival inclding winning the Group 1 Doomben Cup over 2200m on Comin' Through on May 19th.
Michael Walker and Chris Waller after their Doomben Cup win, picture Sportpix.com.au