Emma Raducanu has withdrawn from the Miami Open with a lower back injury.
Raducanu was expected to be in first-round action against China's Wang Xiyu on Tuesday as she continued her comeback at the tournament.
Raducanu was knocked out of Indian Wells after being beaten 6-3 7-5 by Aryna Sabalenka in the third round and she is still yet to win against a top-10 player on the WTA Tour.
Miami features a 96-player singles field with the top 32 seeds in singles receiving a first-round bye. The main draw begins on Tuesday - live on Sky Sports Tennis.
The former US Open champion went down fighting as she was beaten in straight sets by world No 2 Sabalenka having won consecutive matches for the first time since her run to the last 16 of the same tournament last year.
Raducanu has been working with her childhood coach Nick Cavaday following her return from an eight-month absence after surgery on both wrists and ankle.
The 21-year-old, ranked 250th in the world, was scheduled to return to action at the Miami Open after being given a wildcard to play at the 1000 combined tournament.
