The Brisbane weather will determine whether smart mare Black Magic returns to racing on Saturday at Doomben or heads straight to Sydney.

Trainer Bruce Brown is aiming Black Magic at the Group Two Sapphire Stakes at Randwick on April 19 before a return to Brisbane for the major winter carnival sprints.

Brown had entered Black Magic for the Birthday Card Stakes at Rosehill on Saturday but elected to stay home for the Silky Smooth and Speedy Handicap (1200m) at Doomben.

"She is 90 per cent sure to run at Doomben but I won't make a final decision until I see the track rating and what is left in the field," Brown said.

"Black Magic handles the wet but I don't want to knock her around on a really heavy track first-up.

"She has had a trial and I will get (apprentice) Luke Tarrant to claim on her which means she will have just 51 kilos."

The mare won the Listed Juanmo Stakes last year on a dead track and has won her only start on a heavy track in restricted class.

However, Brown is convinced Black Magic will improve on whatever she does on Saturday.

"The run will do her the world of good but I would be disappointed if she didn't race well," he said.

Black Magic hasn't started since she was unplaced behind Heart Testa at Rosehill on November 16.

It was one of three runs for the mare in Sydney last campaign with her best result a second to Hidden Warrior at Rosehill.

Brown rates Black Magic as potentially the best horse he has trained despite having won a Golden Slipper with Calaway Gal in 2002.

Meanwhile, trainer Barry Baldwin has booked in-form jockey Brad Stewart for former Melbourne galloper That's The One in Saturday's race.

That's The One, owned by his breeder and former Brisbane Racing Club chairman Bill Sexton, won four races in Victoria when trained by Colin and Cindy Alderson.

The gelding will be aimed at some of the better winter carnival sprints if he measures up on Saturday.