Great Britain's European champion Gemma Spofforth suffered a broken nose and needed 15 stitches after an accident while out cycling.
The 100m backstroke world-record holder trains at the University of Florida.
A few hours after the crash she said on Twitter: "Doing much better!! Keeping me in over night incase I have a concussion."
Spofforth has endured a difficult year after failing to win a title at the 2010 Commonwealth Games.
She also admitted she nearly quit the sport after illness hampered her bid to defend her World Championship crown in Shanghai, where she was only 23rd fastest in the heats.