Georgina Bloomberg, 27, was knocked unconscious for a short time after her fall last Friday night, but walked out of the arena in Syracuse, N.Y., on her own, The Associated Press reported.
She fell from her horse, Radio City, when the saddle came loose during the middle of a leap over a fence, The New York Times reported.
Bloomberg is scheduled to have a full medical evaluation today, Kraus said. "Despite the injury, she is resting comfortably," Kraus told the New York Daily News.
She was participating in the Syracuse Invitational Sporthorse Tournament at the Oncenter War Memorial Arena.
"The mayor is very concerned, as any father would be," mayoral spokesman Stu Loeser said in a statement.
Bloomberg, one of the nation's top show jumpers, has been injured before. She's broken her back, collarbone, both wrists and an ankle, and has had at least three concussions, the Daily News said.
She's the younger daughter of the mayor and his ex-wife, Susan Brown. In 2007, Georgina Bloomberg was named one of Forbes magazine's "20 Most Intriguing Billionaire Heiresses."