Hear the Ghost has been knocked off the Triple Crown trail by a knee injury, co-owner Ted Aroney told HRTV Thursday afternoon. The winner of the Grade 2 San Felipe in his latest, the Jerry Hollendorfer pupil would have been a top contender in Saturday's Grade 1 Santa Anita Derby.

Aroney, who races Hear the Ghost in partnership with Hall of Famer Hollendorfer, said that the promising sophomore was "off" in his training Thursday morning.

X-rays revealed an issue "developing" in his right knee, prompting the decision to scratch from the Santa Anita Derby and give him the time he needs to heal. Plans call for Hear the Ghost to get 90 days' rest, which ends any hopes of making a Triple Crown race.

His connections have endured similar misfortunes with other Derby hopefuls in the past. Aroney counted this as his sixth prospect who couldn't make the Derby.

Hollendorfer was most famously gutted when then-unbeaten Event of the Year suffered an injury in a workout ahead of the 1998 Derby. Earlier this season, his Fury Kapcori also met with a setback that has kept him on the sidelines.

Hear the Ghost appeared to fill the void left by Fury Kapcori. After impressing in his debut victory at Hollywood Park, Hear the Ghost finished a hard-charging second in the January 21 San Pedro.

The gelded son of Hall of Famer Ghostzapper relished stretching out in distance for the March 9 San Felipe, where he rallied furiously to upset even-money favorite Flashback.

Hear the Ghost and Flashback were set for an eagerly-anticipated rematch in the Santa Anita Derby, until it was called off by Thursday's unfortunate injury report.