Nadal has been struggling with injuries in recent months

Nadal, who has been replaced by Tommy Robredo, decided against competing in North Carolina to avoid aggravating a persistent foot injury.

David Ferrer, Feliciano Lopez and Fernando Verdasco make up the rest of Spain's team.

Nadal also missed Spain's first-round win against Switzerland in February.

The US named their team last week including Andy Roddick, James Blake and doubles pair Bob and Mike Bryan.

The tie will be played indoors at the Joel Coliseum in Winston-Salem, with the winners facing either Sweden or Argentina in September's semi-finals.

Sweden captain Mats Wilander has named an unchanged team for their quarter-final against Argentina in Gothenburg.

Wilander has picked Robin Soderling, Thomas Johansson, Simon Aspelin and Jonas Bjorkman for the tie from 6-8 April.

France will rely on Richard Gasquet and Paul-Henri Mathieu to play singles in their quarter-final against Russia in Moscow.

Michael Llodra and Arnaud Clement will play doubles, while captain Guy Forget has named former French number one Sebastien Grosjean as a reserve despite a lean patch.

Germany captain Patrik Kuehnen has dropped Benjamin Becker for their quarter-final against Belgium, leaving Florian Mayer and Philipp Kohlschreiber as candidates for the second singles slot.

Tommy Haas, who led Germany to a 3-2 victory over Croatia in the first round, will once again lead the side, with Alexander Waske and Michael Kohlmann the doubles partnership.