Astern is still expected to play a part in the spring carnival despite an elevated temperature derailing the former favourite's Caulfield Guineas bid.
The Golden Rose winner was treated on Sunday for the elevated temperature, ruling him out of the Guineas Prelude ahead of next month's main event.
Godolphin said his blood picture was back to normal and a number of other spring options remained for the colt.
"He's made a good recovery but because he will miss the lead-up run on Saturday we had to reconsider running him in the Guineas," O'Shea said on the Godolphin website.
"Nothing has been decided yet, but there are some good options for him which we will assess over the coming days," O'Shea said.