Lawyer Ron, 12th in the Kentucky Derby after being one of the early favorites, is doubtful for the Preakness Stakes because of inflammation in his right hind ankle.
Trainer Bob Holthus told Preakness officials after looking at X-rays, "We probably aren't going to come." The May 20 race is the second leg of the Triple Crown.
"Unless something good happens before Saturday, it doesn't look favorable," said Holthus, who'd said after the Derby that the Arkansas Derby winner "didn't have any punch" in the race.
Of the top four Derby finishers, only Brother Derek, the morning-line favorite who finished in a dead heat for fourth after starting from an outside post and losing a shoe, is expected to challenge winner Barbaro again in the Preakness.
Bluegrass Cat, Steppenwolfer and Jazil are pointed toward the Belmont Stakes on June 10, their trainers said.
Sweetnorthernsaint, the 5-1 betting favorite in the Derby who was third after a mile but tired down the stretch and finished seventh, will join Barbaro and Brother Derek in the Preakness in what will be a considerably smaller field than the Derby -- perhaps eight to a maximum of 14 horses instead of 20.
Expected starters who weren't in the Derby are Gotham Stakes winner Like Now, Withers winner Bernardini, and Simon Pure.
Trainer Bob Baffert, who had three horses in the Derby, said he would make a decision this weekend about which of them might run in the Preakness, focusing on Point Determined and Bob And John, with Sinister Minister doubtful.