UNDATED -- Days after competitive eating legend Takeru Kobayashi revealed he has an arthritic jaw, San Jose's Joey Chestnut launched a war of words on Thursday. Chestnut believes Kobayashi may be avoiding a showdown at July 4th Nathan's hot dog eating contest.

Chestnut recently broke Kobayashi's world record by downing 591/2 dogs in 12 minutes. At last year's Nathan's contest he fell a mere dog short and many consider him a favorite in this year's eat-off.

"I hate to call anybody a coward, and I wouldn't call him that," said Chestnut, 23, from his San Jose home. "But I don't know. He's shown up the six previous years. It's a strange coincidence, now that he's the underdog."

Kobayashi, the six-time defending Nathan's hot dog eating champion, revealed on his blog earlier this year that he had received a chilling diagnosis: Jaw pain that limits how far he can open his mouth.

The disclosure set stomachs rumbling throughout the dog-eat-dog world of competitive eating in the days before the annual Independence Day chowdown.

On his blog, the 29-year-old said a mouthful with the news that he was visiting a specialist and a chiropractor for relief of the bum jaw. "Already I can't open my jaws more than just a little bit," he wrote.

Word of the champ's woes spread quickly from Kyoto to Coney Island.

Some believe it is a ploy to unnerve Chestnut, his bun-swallowing rival. Kobayashi was keeping his mouth shut Thursday, although he issued a statement promising to pursue treatment. "I intend to do everything I can to treat this condition in what little time I have," he said.

A weak jaw won't cut the mustard in a competition where the winner will likely need to down more than 50 hot dogs and buns. During his six years as the Nathan's champion, the 165-pound Kobayashi has consumed 3011/4 hot dogs -- a string of performances that made him the Michael Jordan of mass consumption.

His personal best was 533/4 last year. Chestnut, who smashed that mark June 2 in Phoenix.

No less an expert than Washington Post columnist Tony Kornheiser, on his ESPN show "Pardon The Interruption," suggested Kobayashi was trying to lull Chestnut into lowering his guard.

"I think he's playing possum," Kornheiser said.

Chestnut, despite his skepticism, acknowledged Kobayashi might have strained his jaw while training for the event.

"Your jaw and the muscles in your esophagus are the first to get sore," he explained.

The Japanese have recently dominated the annual event, which started on Brooklyn's beachfront in 1916. The only American winner since 1996 was New Jersey's Steve Keiner in 1999. Two years later, Kobayashi -- whose voracious appetite earned him the nickname "Tsunami" -- began his belly busting reign.

Kobayashi plans to appear in Coney Island for Wednesday's event even if he can't compete, said Rich Shea, one of the founders of the International Federation of Competitive Eating.

At the very least, Shea hoped, Kobayashi would present this year's winner with the mustard yellow belt emblematic of eating excellence.

"I think, like all great champions, Kobayashi doesn't want to shy away from competition," said Shea. "But I don't want to put words in his mouth. And if I did, they'd have to be monosyllabic -- not too much for him to swallow."