Simona Halep was forced to withdraw from the Miami Masters with a toe injury ahead of her second-round match against Casey Dellacqua.
The world number five had a bye from the first round, and had been due to face the Australian wildcard this evening, but pulled out just a couple of hours before her match with the injury.
Jana Cepelova took the Romanian's place in the draw as a lucky loser, but lost in three sets to Dellacqua.
Halep reached the semi-finals at Indian Wells last week, moving her into the top five in the world rankings for the first time.