"If we can't fix up anything for Orcadian then that will have to be it for the season," he said. "It will be nice to have a new term to look forward to with him and plan accordingly.
Eustace has trained for Smith since taking out a license and buying the Breeders' Park Lodge yard in Park Lane, Newmarket and has usually managed a decent race-winner for his client at least once-a-year.
"This one came at just the right time because we had not a particularly good season," Eustace added.
A further 12 races on existing meetings at Dunstall Park to take place throughout November and early December were also announced. They have been introduced to provide extra opportunities for horses who are "missing out" under the new handicap system, which started on 1 September.
Explaining the move, the BHB's Mike Waring said: "We are conscious of the fact that there are horses missing out at the bottom of bands and we are trying to put on extra opportunities for them."
The additional fixtures will take place on 3, 4, 5, 11 November and 1, 15 December.