Rafael Nadal will be out of action for between four and six weeks with a stress fracture of the rib.
The injury occurred in Saturday's Indian Wells semi-final against Carlos Alcaraz.
Nadal progressed to the final but lost against Taylor Fritz, when he found breathing painful and complained of dizziness.
The 21-time Grand Slam champion could miss both of next month's clay court events in Monte Carlo and Barcelona.
The French Open, which is the year's second major, begins in Paris two months.
More to follow.