Thais, who was entered in Saturday’s $2 million Breeders’ Cup Filly and Mare Turf at Santa Anita to act as a pacemaker for probable favorite Sistercharlie, was scratched on Thursday based on the recommendation of Dr. Rick Arthur, the equine medical director for the California Horse Racing Board.

“She was placed on the vet’s list as unsound,” Arthur told Daily Racing Form Thursday, declining to get into specifics of the unsound area.

Thais is trained by Chad Brown and owned by Peter Brant. Thais has run in three consecutive Grade 1 stakes to ensure there would be pace for Sistercharlie who won all three of those races _ the Diana, Beverly D and Flower Bowl. As recently as Saturday, Thais worked five furlongs in 1:00.80 in company with Sistercharlie at Belmont Park before both mares shipped to Southern California on Monday.

“She was taken out of the race by the chief veterinarian here,” Brown said. “I disagree with it, this filly’s been extremely sound in all of her works, races and daily training. Unfortunately, it’s not our call so we’re just going to move on into the race and hopefully Sistercharlie can still work out a good trip.”

Brown noted that Thais was in last year’s Breeders’ Cup Filly and Mare Turf, but broke poorly and never got to the lead, but Sistercharlie still won.

“We had her in there for a reason so obviously we felt it was in Sistercharlie’s benefit to have Thais in the race,” Brown said. “So in that regard it makes it more challenging. That said, Thais was in the race last year, missed the break and was never better than fifth I don’t think whole way, did no work, and [Sistercharlie] was able to win.”

The scratch of Thais reduces the Filly and Mare Turf field to 11. Mirth, winner of the Grade 1 Rodeo Drive on the front end here on Sept. 28, could play out as the primary speed.