Glyn Schofield will fight a five-week ban over his handling of Number One Gun in a race at Randwick.
The high-profile jockey was hit with the suspension at the conclusion of an inquiry on Tuesday and immediately signalled his intention to appeal.
Number One Gun ran 2-1/2 lengths second to Rowie in a 1400m race on the Kensington track on December 20 after clocking a time close to the course record for the first 1000 metres.
Number One Gun clocked 56.62s, 0.02s outside the 1000m track record.
He ran his first 800m, 3.22s or 20 lengths faster than the average for 1400m races since the re-opening of the Kensington track in October.
Racing NSW stewards found Schofield guilty of failing to take all reasonable and permissible measures to ensure the horse was given every opportunity to win the race.
They also said he had erred by failing to make an effort to restrain Number One Gun, particularly between the 600 and 400 metres by riding the horse along when he was already six lengths in front.
An examination of betting records on the race found no irregularities.
Schofield vigorously defended the charge, saying he had made a concerted effort to slow the pace.
In a crowded leader board for the Sydney premiership, Schofield is equal third with Hugh Bowman on 26 wins for the season behind Christian Reith on 30 and Tommy Berry on 27.
As the suspension stands, Schofield will begin the ban on Sunday and be back riding on February 16.
Stewards said the penalty had been discounted to reflect Schofield had not been charged with such an offence in 30 years of riding.