TOKYO (AP) Kentucky Derby winner Sunday Silence is fighting for his life after developing a debilitating disease in his left foreleg, a newspaper reported Sunday.

Shadai Stallion Station spokesman Eisuke Tokutake said the 1989 Kentucky Derby and Breeders' Cup Classic champion might have to be euthanized within a week, according to The Japan Times.

Sunday Silence developed an inflammation of soft tissue in the hoof, called laminitis, about two weeks ago and the stallion's condition has gradually worsened, the English-language newspaper reported.

The 16-year-old dark bay colt is being treated at the Stallion Station on Japan's northernmost island of Hokkaido.

Secretariat was euthanized after contracting laminitis in 1989.

Sunday Silence's rivalry with Easy Goer stirred memories of Affirmed's duels with Alydar a decade earlier.

Sunday Silence beat favored Easy Goer by 2½ lengths in the 1989 Derby, then won a stretch duel with Easy Goer in the Preakness.

Easy Goer avenged the earlier losses in the Belmont, defeating Sunday Silence by eight lengths and denying him the Triple Crown.

The two met again in November 1989. Sunday Silence beat Easy Goer by a neck in the $3 million Breeder's Cup Classic. Sunday Silence was named the 3-year-old champion and the Horse of the Year in 1989.

In June 1990, Sunday Silence was sold to Shadai Farm in Japan and became a dominant stallion, eventually siring 1995 Japanese Derby Winner Tayasu Tsuyoshi.

Sunday Silence won nine races in 14 career starts, earning $4,968,554. He was inducted into horse racing's Hall of Fame in 1996.

The information contained in the AP News report may not be published, broadcast or redistributed without prior written authority of The Associated Press.