World number two Rafael Nadal [ Images ] has been left out of Spain's Davis Cup team which travels to face the United States in the quarter-finals next week.

In his place, Tommy Robredo [ Images ] has been called up alongside David Ferrer, Feliciano Lopez [ Images ] and Fernando Verdasco [ Images ].

Nadal decided against competing to avoid aggravating persistent muscular problems, captain Emilio Sanchez Vicario said on Tuesday.

Nadal was unable to play in Spain's 3-2 win over Switzerland [ Images ] in the first round in February because of a late injury.

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

The tie will be played indoors at the Joel Coliseum in Winston-Salem, North Carolina, between April 6-8.

The winners will face either Sweden or Argentina in the semi-finals from September 21 to 23.