Signoff's Adelaide Cup campaign will hinge on results of tests taken from the class stayer after his searching gallop at Caulfield.

Signoff has not raced since returning an irregularity to the anti-inflammatory ibuprofen after his first-up win in the Lord Stakes on December 26.

Trainer Darren Weir scratched the horse from a race at Flemington last month and again on Saturday as he didn't want to take the risk the horse might produce a positive test despite three recent negative readings.

Signoff was given a hit-out on Saturday before the opening race and Weir said results of samples taken post-gallop should be known by Thursday.

Signoff will be entered for a 2500m race at Moonee Valley on Friday.

Weir said Signoff had been treated with ibuprofen for 28 days as part of his rehabilitation from a tendon injury, four months before he had his first run back.

He is hopeful the latest test will also be negative.

"I've done everything possible then," Weir said.

"I've taken him to the races, I've worked him at home. I've taken them (tests) at all different times. After work, before work. So we've done all we can do really.

"There's either two options. Either chuck the horse in the paddock and not know when he can come back or (play) Russian roulette and go to the races."

Brad Rawiller, who rode Signoff in Saturday's gallop, said the last 1000m of the hit-out was strong and the horse could still be a force in next month's Adelaide Cup.