Efficient has been promoted into Saturday’s Cox Plate field despite not having won a race for more than two years.
The Lloyd Williams-owned 2007 Melbourne Cup winner will carry the number one saddle cloth in the 14-horse field.
Triple Group One winner Yosei has been named second emergency behind Avienus who has yet to win at the highest level but finished second to Descarado at her most recent start in the Caulfield Stakes.
The Gai Waterhouse-trained Descarado is battling a leg injury but Waterhouse says she expects him to take his place.
Moonee Valley Race Club chairman Bob Scarborough said Efficient deserved his place on past performances.
“We felt he should be given his opportunity,” Scarborough said.
“Yosei’s current form is not as good as some of the others.”