World number seven Tomas Berdych has withdrawn from the Barcelona Open due to illness, organisers said on Tuesday.
The Czech fifth seed has gastroenteritis and will be replaced in the draw by Rui Machado of Portugal, according to the tournament website (www.barcelonaopenbancsabadell.com).
Britain's Andy Murray, who lost to Nadal in the semi-finals in Monaco and is seeded second in the Catalan capital, is struggling with an elbow injury.
An ATP spokesman said he would train on Tuesday before making a decision on whether he can compete.
Nadal cruises into first US Open final
Andy Murray beats Federer to clinch Toronto title
Nadal to start U.S. Open against Gabashvili
Nadal gets standing ovation at Real Madrid game
Murray top seed in LA after Djokovic withdraws