Rafael Nadal will be out for between four and six weeks after suffering a stress fracture of his rib in Indian Wells last week.
The Australian Open champion sought treatment during his semi-final victory over Carlos Alcaraz and was clearly hampered in a straight-sets defeat by Taylor Fritz on Sunday, his first loss of the season.
Writing on Twitter, Nadal said: “Hello everyone, I wanted to announce that I have returned to Spain and I immediately went to visit my medical team to do the tests after the Indian Wells final that I played with discomfort.
“As it turns out, I have a stress crack in one of my ribs and will be out for four to six weeks. This is not good news and I did not expect this.”
The Spaniard will almost certainly miss the Monte-Carlo Masters and the Barcelona Open, tournaments he has won 11 and 12 times respectively, and he could also be forced to sit out the Madrid Open at the beginning of May.
The ATP Tour continues this week with another Masters 1,000 level event in Miami.