Trainer Barry Baldwin is struggling to get fan favourite The Candy Man ready for the Group One Doncaster Mile.

The Candy Man turned in what appeared the poorest run of his career when sixth in the $1 million Magic Millions Trophy (2400m) on January 14.

The gelding was diagnosed with thumps after the run which could have explained the effort.

However, Baldwin has since discovered The Candy Man pulled a muscle in his rump during the race.

"He has been sore all along his bottom. I am beginning to wonder if he even had the thumps and the rump injury is the more likely reason for his Millions run," Baldwin said.

"It is taking a while to treat including with ultra sound. The thing is we haven't been able to gallop him although he has done some work."

Baldwin said The Candy Man would need at least one run before the Doncaster at Randwick on April 4.

" I am hoping he will be ready for a public gallop at the Gold Coast or in Brisbane next month but time is running out," Baldwin said.

"If he isn't ready for the Doncaster we can start thinking about the Brisbane winter."

Meanwhile, Baldwin has promising stayer Grand Shanghai in a benchmark race over 2200m on Saturday and a 2400m race at the Sunshine Coast on Friday night.

Grand Shanghai won a maiden at Toowoomba over 2200m by five lengths two weeks ago.

"I know it is a big step up in class no matter which way we go but I want to test him as a possible Derby horse," he said.

"We will decide on Thursday which way to go."