Trainer Robert Heathcote says Jopa's Doomben impost highlights issues with Queensland's ratings-based handicapping system.

Jopa has risen sharply in the weight to 59kg for a last-start win when he contests Saturday's GPK - Your Technology Partner Handicap with Brooke Stower replacing Bridget Grylls.

Heathcote said Jopa was not a big horse and he had no choice but to use a claiming apprentice.

"Bridget did a good job last time and we would have liked to use her again. But in the end Brooke has a three-kilo claim and we decided to go with her," Heathcote said.

"Brooke rode a winner for me at Ipswich recently and she is a confident young rider who is getting used to metropolitan racing."

He said the weight situation wasn't uncommon with the way horses were handicapped in Brisbane.

"It happens often enough when horses go up sharply in weights in Brisbane for winning just one race," Heathcote said.

"But where you really see the difference is when horses come up from Sydney because they are rated a different way to us.

"Often you will get a Sydney horse with Group form getting weight from one of ours which has been highly rated on performances solely against Brisbane horses."

"An example was my mare Fillydelphia who ran second two years in a row in the Bernborough Handicap and each time was beaten by Sydney geldings who had won stakes races but were getting weight from her."

Heathcote said he feared what might happen this winter with a huge influx of Sydney horses expected this year.

"It makes it very hard for us to win a stakes race in our winter," he said.

The Heathcote-trained Oberland will not back up from his win at Doomben on Wednesday after drawing the outside barrier in the three-year-old sprint.