O'Brien had the likes of Deauville and Idaho among his original entry, but only JP McManus' Dundalk regular remains among 14 in contention for the Lingfield showpiece.
Last year's winner Convey is one of two Sir Michael Stoute possibles along with Autocratic.
Khalidi could make his debut for Clive Cox after leaving John Gosden, who is likely to be represented by Utmost after his win in the trial for this race.
The progressive Star Archer stands his ground for Hugo Palmer, with Mr Owen, Petite Jack and Richard Fahey's nine-year-old Gabrial other possibles.
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