2-year-old filly Set the Tone euthanized after hitting a fence in training accident at Del Mar

DEL MAR, Calif. -- A 2-year-old filly was fatally injured in an accident during training hours at Del Mar on Wednesday.

Del Mar Thoroughbred Club President Josh Rubinstein announced the death during a safety briefing for the Breeders' Cup, which will be held at the track north of San Diego on Friday and Saturday.

The filly named Set the Tone dumped her exercise rider and ran off, hitting a fence and severely injuring her shoulder. Veterinarians attempted to save her, but it wasn't possible and she was euthanized. The rider wasn't injured.

Trained by Bob Hess Jr., Set the Tone was winless in three career starts, including two second-place finishes. She had career earnings of $12,300. She was a daughter of 2014 Belmont Stakes winner Tonalist.