Just when it seemed he was immune to the ravages of time and the infirmities of the flesh, John Henry has developed a leg problem that might keep him out of the $2 million Breeders' Cup turf race. Trainer Ron McAnally said this morning that the 9-year-old had developed a swelling in his left front ankle, but he wasn't sure of the cause. He hoped the swelling might simply be a reaction to a topical medication that had been applied to the leg.

If that were the cause, John Henry could run at Hollywood Park Nov. 10. But, McAnally said, "If the filling (the swelling) is from the anatomy of the horse, then he'll be on the shelf for a while. We should know in the next two or three days."

Owner Sam Rubin, who made an initial $133,000 payment to make John Henry a supplementary nominee to the Breeders' Cup, was not optimistic. He said there was an "80 percent chance" his gelding would not be able to run Nov. 10.

"If there's even a 50-50 chance," Rubin said, "Ron McAnally will put up the balance of the $400,000 entry fee. But if John Henry cannot run we will forfeit the $133,000 that we put up on Tuesday."

The loss of John Henry would be a great blow to the Breeders' Cup. He is the world's leading money-winning thoroughbred and the top box-office attraction in U.S. racing. His absence would surely hurt both the live gate and the television ratings for the Cup.

At an age when almost all thoroughbreds are retired or long past their prime, John Henry had been enjoying the most productive year of his life. He has won his last six turf races, amassing earnings of more than $2 million this year and $6.5 million for his career.

He had been training well for the Breeders' Cup and on Sunday worked six furlongs in 1:11 3/5. He went so smoothly that McAnally has reason to hope that the swelling is due to a skin irritation rather than a serious physical problem.