Grade 2 Peter Pan Stakes winner Mark Valeski is "doubtful" to return for the Belmont, trainer Larry Jones told Daily Racing Form Monday.
"Mark's actually doing OK, but he got a little tired after the race," Jones said. "He doesn't have the same energy level.
"I'm not saying he's 100 percent out. But we may end up bypassing the Belmont and just waiting for the Dwyer (Grade 2 going 1 1/8 miles at Belmont Park June 30)."
Also on Monday, trainer Dale Romans told DRF that Javier Castellano will pick up the mount aboard Dullahan in the Belmont.
The jockey change comes after the colt's former rider, Kent Desormeaux, failed a breathalyzer test last Friday.
Dullahan, the only horse besides Hall of Famer Round Table to turn the Grade 1 Breeders' Futurity/Blue Grass double at Keeneland, was most recently third in the Kentucky Derby.