Chris Munce has called on his old mate Larry Cassidy to help end stayer Perplexity's longest losing streak.

Cassidy and Munce were rivals as jockeys in many Group One races before Munce retired to take up training last year.

Munce has been supporting Cassidy with rides since the latter came back to racing in August after a long injury break including Perplexity who runs in Saturday's Open Hcp (2000m) at Doomben.

Perplexity has won five races and about $300,000 prize money since joining Munce's stable 18 months ago but his last victory was on November 21 last year.

Munce said it had been frustrating because Perplexity had been racing well in his eight runs since his last win.

"It has just been a combination of things. Big weights, distances being too short or races being run the wrong way," Munce said.

"But he always tries and in these staying races they all seem to have their day."

Munce said he decided a change of jockey might help Perplexity and Cassidy had won many Group One staying races.

"The staying races in Brisbane are often a tactical battle so we will see what Larry can come up with," he said.

Cassidy will also stick with the Munce-trained Wicked Intent in the Queensland X Ray Open (1110m).

"Larry was happy to stick with him after they combined to run second first-up. The wide barrier is no help but he has done well since," Munce said.