Babcock said that if Williams committed a "major offense" at a Grand Slam tournament in 2010 or 2011, her fine could be doubled and she would be barred from the following U.S. Open.
Serena hit with $2,000 fine for
abusing umpire →
Bill Babcock, director of the Grand Slam Committee, said the biological passport program "is essential to ensure that tennis remains a clean sport for the future."
Tennis adopts biological passport for anti-doping →