Apprentice Tom Sadler has been cleared of any breach of the rules of racing over his ride on Supreme Warrior at Sandown last week after stewards accepted evidence his vision had been impaired by mud during the race.

But deputy chief steward Robert Cram told Sadler his performance on the horse remains of serious concern.

Sadler received the "benefit of a very grave doubt" in relation to his handling of the Leon Corstens-trained galloper who was ridden in contrasting style to its previous few runs and had failed to take obvious runs in the straight.

Supreme Warrior, a front-runner at his most recent starts, settled at the rear of the field in the Sandown race.

In the home straight he stayed near the inside as the field fanned on the heavy track and Sadler appeared content to maintain his position behind another runner over the final 400m displaying little or no vigour.

But Sadler told the stewards he believed it would have been unsafe for him to have done otherwise.

"At the time I couldn't see," Sadler told the stewards.

"I wasn't confident enough to run up between horses in the dark."

Asked what he was thinking as he sat still on his horse from the 300m, Sadler said he was wishing he had a second pair of goggles.

Sadler's advocate, jockeys' association president Des O'Keefe, said the heavy conditions in the race, the last of the day, were "appalling".

"The backwash he was copping was the worst in the race," O'Keefe said in evidence.

"He had no confidence to go for those runs."

While no charge was laid against Sadler, stewards charged Corstens, who was in Queensland on the day of the race, for failing to notify them of a change in riding tactics.

He received a reprimand and was reminded of his obligations.