The back-up specialist is set to contest the Listed Takeover Target Stakes (1200m) at Gosford this weekend but after drawing the outside gate in the 16-horse field, he has his work cut out.
However, Williams is taking a slightly longer-term view, hoping Shelby Sixtysix can turn in a competitive performance on Saturday before reverting to his proven formula and heading to the Doomben 10,000 seven days later.
"We were looking at the weather for Queensland next week and they're forecasting a lot of rain leading into Saturday," Williams said.
"I'm contemplating going to Gosford and seven days later running in the Doomben 10,000.
"There's a lot of questions to be answered before we go up there and one of those is, would he definitely get a run?"
Shelby Sixtysix was one of the feelgood stories of the Sydney autumn, racing on five consecutive Saturdays and relishing the heavy tracks to split Eduardo and Nature Strip in the Challenge Stakes before winning the Maurice McCarten Stakes and Galaxy.
The five-year-old's soundness issues mean Williams is rarely able to gallop him between runs and for that reason he admits he may need the hit-out on Saturday.
"He is just lacking recent racing. I know he only ran a fortnight ago, but he has only had the two runs in five weeks and it's not the routine I would have liked," Williams said.
"(Barrier 16) makes it very difficult around a track like Gosford that suits on-speed horses. He hasn't got the speed to cross them.
"We will just have to see how it pans out."
Godolphin's Gravina has opened a $4 favourite for the Takeover Target with Shelby Sixtysix prominent at $5.
The race is one of three features on the stand-alone Saturday program along with the Listed Gosford Gold Cup (2080m) and $500,000 The Coast (1600m).