His announcement came as a surprise to fellow contestants and the trainers on NBC's weight-loss competition show. "That is so strange," said trainer Jillian Michaels.
An NBC spokesperson said Gardner "is not doing interviews at this time," and calls to his Logan gym went unanswered.
NBC released a statement that "Rulon chose to leave the show for personal reasons and we respected his wishes. We wish him well."
Gardner released a statement through his reps at 776 Original Marketing in Colorado Springs, Colo., calling his experience on the show "fantastic" and asserting that he has "accomplished" his goal "to get my life and my health back."
During his time on the show, Gardner got down to 301 pounds from his starting weight of 474 a loss of 173 pounds. He weighed 264 pounds when he competed in the 2004 Olympics.
"Once I reached my goal and started feeling like my old self, I felt compelled to return home and support my wife, Kamie, in the ongoing management of our personal and professional affairs," he said. "Another exciting outcome is that I am strongly considering a return to competitive wrestling."
Gardner won a gold medal in Greco-Roman wrestling at the 2000 Olympics, and followed that with a bronze medal at the 2004 Games. He then announced his retirement from the sport.
Gardner's rep pointed to a story on www.themat.com, which reported that Gardner had returned to the U.S. Olympic Training Center in Colorado Springs over the weekend for wrestling workouts.
"My competitive fire is back," Gardner is quoted on a website posting. "I am contemplating competing again."
On the Web, speculation is swirling around Gardner's reasons for quitting "The Biggest Loser." Articles and postings on various fan sites are theorizing on everything from Gardner's supposed petulance when he lost a challenge on Tuesday's episode and a chance to have his picture on a Wheaties box to gossip about possible family problems.
"I didn't come here to create a relationship with anybody," Gardner said on the show. "I came to learn about a lot of my issues ... I think, for the most part, I'm ready to go home."
And to the U.S. Olympic Training Center.
O Past episodes of "The Biggest Loser" are available at www.NBC.com.