The Darren Weir-trained Signoff has returned an irregularity following the comeback stayer's win at Caulfield last month.

Acting chief steward Robert Cram said Weir was informed of Signoff's irregularity to ibuprofen on Friday.

Connections decided not take a chance that the stayer may return another irregularity and scratched him from the Piping Lane Handicap at Flemington on Saturday.

"Mr Weir discussed it with the owners of Signoff and decided to scratch," Cram said.

"They didn't want to take any undue risks with the erratic excretion of iboprofun."

Cram said there has been a spate of irregularities in Victoria to ibuprofun with trainers Archie Alexander and Clinton McDonald being fined after recent winners Red Shift and Rib Eye returned positive swabs.

He said trainers had been told in October and again last week about the difficulties in predicting the clearance time of the drug.

Ibuprofun is a non-steroidal anti-inflammatory and a prohibited substance under the rules of racing.

Cram said ibuprofun was not registered for use on horses.

Signoff had been off the scene for eight months with a tendon injury before returning to win the Listed Lord Stakes at Caulfield on December 26.