The American team will play Italy in the quarterfinals July 19-20 in Washington. Italian captain Corrado Barrazzutti has until July 9 to name his team.
Seles, 29, has been a member of 11 Fed Cup teams, winning titles in 1996, 1999 and 2000. She has a combined singles and doubles record of 17-2 in Fed Cup play.
Shaughnessy, 24, who will be representing the U.S. for the fourth consecutive Fed Cup, reached her first Grand Slam quarterfinal at the 2003 Australian Open.