A treatment mistake has ruled Benaud (Reliable Man) out of the Gr.1 Metropolitan (2400m) at Randwick on Saturday.

Trainer John O’Shea informed stewards on Monday morning that the gelding was mistakenly given medication which contained a prohibited substance.

“Trainer Mr John O’Shea has this morning informed Racing NSW Stewards that Benaud, which was being aimed at The Metropolitan, will not be declared as an acceptor in this race,” a Racing NSW stewards statement read.

“Mr O’Shea has informed Stewards that Benaud was inadvertently treated with a medication this morning containing a prohibited substance and therefore is unable to compete in the event.”

Out of broodmare gem Baggy Green (Galileo), the Reliable Man four-year-old had returned in good form this spring after finishing runner-up in the Gr.1 Australian Derby (2400m) earlier this year.

He posted a sixth placing in the Gr.1 Winx Stakes (1400m) first-up before jockey William Pike guided him to fourth in the Gr.2 Chelmsford Stakes (1600m), and runner-up in the Gr.3 Kingston Town Stakes (2000m).

While he will be unable to compete, his half-brother No Compromise (NZ) (Pins) will attempt to bring home the silverware for the family.

Trained by Chris Waller, the Pins six-year-old finished third in the Gr.2 Chelmsford Stakes (1600m) two starts back before running sixth in the Gr.3 Kingston Town Stakes (2000m).