Hansen was monitored by team doctors during the night. USA Swimming team physician Ken Haller decided that Hansen should not swim in the 200m breaststroke heats on Thursday. Hansen is expected to rest for a few days, and is likely to be well in time for Sunday's 4 x 100m medley relay.
Hansen was about to enter his favorite race, where he and Japan's dual Olympic gold medallist Kosuke Kitajima would battle for the 200m breaststroke title. Now it looks like Kitajima will be a certain winner.
Hansen's teammate, Aaron Peirsol, said the team was disappointed that Hansen would not be able to compete in his favorite event. "He's one of those guys if he could swim, he would do anything to do so, so he must be feeling pretty sick," Peirsol said. "He would have done so well, so I'm really upset."

