Missy Franklin reacts after placing last in a women's 200-meter freestyle semifinal during the swimming competitions at the 2016 Summer Olympics, Monday, Aug. 8, 2016, in Rio de Janeiro, Brazil.

(AP Photo) 

Missy Franklin had been waiting around three days to compete in the Rio Olympics. She finally got in the pool Monday only to endure another disappointment in the most unsettling year of her career.

As she struggled to keep up in the 200m freestyle semifinal, an NBC's announcer said in disbelief, “There’s no better racer than Missy. We saw that four years ago, that just doesn’t disappear.”

Franklin finished last in her heat with only the 13th-fastest time among 16 swimmers. Touching in at 1 minute, 57.56 seconds, she was actually slower than her time in the afternoon preliminaries.

"I wish I could tell you," Franklin said to ESPN when asked what went wrong. "I gave it everything I had and it just wasn't there. I did the best I could."

As a bubbly, 17-year-old high schooler, Franklin won four golds and a bronze at the London Games. But she's endured a mystifying loss of form since turning pro last summer, struggling just to qualify for two individual events and a relay at the U.S. trials. Her coach, Todd Schmitz, told ESPN that injuries are unlikely the culprit.

"I definitely think it's something more than physical," Schmitz said. "Obviously, we saw a little bit of that manifest itself at trials. There is clearly something that is not connected. She was nervous this morning -- you could see it."

Franklin spoke with Colorado Matters earlier this year about getting ready for the Rio Olympics, explaining that her goal is not a certain number of medals. 

"Going into a meet, I never, ever set a medal goal," Franklin said. "I never go in there thinking, 'I want to win this number of medals and I want them to be this color.' Because in my mind, that's me basing my goals on other people. I have no idea, and I have no control over what my competitors are going to do... and if I have no control over it, that's wasted energy."

In 2012, Franklin competed in seven Olympic events. Now, all she's got left is the 200 backstroke and a likely spot on the 4x200 free relay team.