Rafael Nadal said on Tuesday he would be out of action for between four and six weeks with a stress fracture in one of his ribs.
"This is not good news and I did not expect this," tweeted Nadal, who will miss the start of the claycourt season.
The Spaniard will be ruled out of the Monte Carlo and Barcelona tournaments although he could potentially return for the Madrid Masters on May 1-8.
Nadal, who won the Australian Open title this year, lost to American Taylor Fritz in the final of the Indian Wells Masters on Sunday, ending his perfect 20-0 run to start 2022.
He said he had played Indian Wells with "discomfort" and so had undergone medical checks on his return to Spain.
"I have a stress fracture in one of my ribs and will be out for 4 to 6 weeks," Nadal said.