KANSAS CITY, Mo. (AP) — Adam Rippon was warming up for practice late last week, preparing to defend his U.S. figure skating title, when a seemingly innocuous movement was met with a loud crunch.

He knew immediately that he had broken his left foot.

X-rays and an MRI exam confirmed a sprain and broken fifth metatarsal, which will keep Rippon off the ice up to three months. And that means he'll not only miss next week's nationals in Kansas City, but also the world championships in March, where he will hope his compatriots perform well enough to give the Americans three spots for the Pyeongchang Olympics.

"I hope the officials, the fans and the judges won't forget about me in the next few months," Rippon said Monday. "I feel like I made huge strides and I've been coming into my own."

The national championships also lost women's contender Polina Edmunds, a 2014 Olympian, who was hoping to compete despite a bone bruise in her right foot that has kept her out all season.

"I'm disappointed that I will miss the 2017 U.S. Championships and wish all the athletes good luck in Kansas City," the two-time silver medalist said in a statement Monday. "I will continue to focus on my health and look forward to a full return to ice."

Edmunds' decision to withdraw leaves Gracie Gold and Ashley Wagner, who have combined to win the past five titles, the heavy favorites when competition begins next week.

Rippon's injury gives his training partner, Nathan Chen, the inside track following his bronze medal at the Grand Prix Final last month. Former champions Jason Brown and Max Aaron will also compete.

"I won't take this lying down, which is ironically what I'm doing right now," Rippon said, "but I will use this as a chance to rehab smaller injuries I've been dealing with. I can work on my flexibility. I can work on my conditioning. Only my left ankle is hurt. There's still a lot I can improve."

Rippon said his injuries won't require surgery, though he will have another round of examinations in about four weeks to see how he's healing. He plans to remain at home in Los Angeles during nationals before continuing his recovery at the U.S. training facility in Colorado Springs.

"I don't feel like I'll only come back from this. I feel like I have laser focus to be much better because of this," he said. "When I was sitting on the bench near the rink immediately after I broke my foot, my first thought was, 'This is my story. I'll be at the Olympics.'"

That happy ending might only happen if the U.S. has two men whose combined placement at worlds is 13th or better, because that would give its contingent three spots in South Korea. If only two skaters qualify, there is a good chance Rippon could be left off the team if he is not at his best in the 2018 nationals, which basically serve as the Olympic trials.

"The way I see it, I have 12 months before next year's national championships in San Jose, and then the Olympic Games," Rippon said, "and 12 months is more than enough."