Holthus informed the Del Mar racing office Aug. 8 that his 3-year-old Pure Prize filly won't be making the trip from Kentucky for the 1 1/8-mile turf event, where she was expected to have a rematch with American Oaks runner-up Satan's Circus.
In a follow-up telephone interview, Holthus said, "That trip to Hollywood Park took more out of her than we expected. And then when we got back here to Kentucky, we had about a week of 100-degree weather and the combination of the two just knocked her out.
"There's nothing else wrong; it's just that she's pretty knocked out. We're very disappointed we won't be able to come out there."
Pure Clan, third-place finisher in the Kentucky Oaks (gr. I) this spring, has won all four of her starts on turf and went over the $1 million mark in lifetime earnings with her American Oaks victory. Lewis Lakin, IEAH Stables, and Pegasus Holding Group Stables own her.
The Oaks will be the next start for the Christophe Clement-trained Satan's Circus, the French invader who put in her final work for the race Aug. 9. Nicholas Bachalard, assistant to Cristophe Clement with the string at Del Mar, supervised the drill as the filly covered a half-mile over the Polytrack racing surface in :49 1/5.