Andy Murray has withdrawn from the Brisbane International because of issues with his long-term hip injury.
The 30-year-old has dropped to 16th in the world rankings, having not played since July.
Murray had been given a bye to the last 16 in Brisbane and was due to play American Ryan Harrison on Thursday, but said his right hip is still not ready for match conditions.
Murray’s withdrawal is a bitter blow for tournament directors who already lost Nadal before the event through injury, while number one women’s seed Muguruza retired in her opening match after suffering severe cramps.
“It’s disappointing that Andy can’t continue. It’s disappointing for him because I know how much he wanted to play here as well,” tournament director Cameron Pearson told the ABC.