Flatt won a silver medal at the 2011 U.S. Championships. She was sent to the 2011 World Championships. A week before the event, Flatt was diagnosed with a stress fracture in her right tibia (her landing leg). Nevertheless, her coach Tom Zakrajsek stated that he felt that Flatt could complete her elements despite the stress fracture and did not request that the alternate, Mirai Nagasu, compete in her place. During the competition, Flatt had errors on one of her jumps in the short program and three in the free skate and finished in 12th place. In May 2011, Flatt confirmed that she was leaving Colorado Springs in order to study chemical engineering at Stanford University and would look for a new coach in the Bay Area. In June 2011, U.S. Figure Skating reprimanded and fined Flatt for not informing them of her injury in advance.