Bernard Tomic plans to sit out the season's so-called fifth major as he awaits the results of scans for a problematic right wrist injury.
The Australian No.1 struggled throughout his third-round match in Indian Wells before retiring while trailing big-serving Canadian 12th seed Milos Raonic 6-2 3-0 on Monday.
Tomic has battled the injury since the Australian Open in January, and lasted just 36 minutes against world No.14 Raonic and won just 18 points.
The 23-year-old was already in doubt for next week's Miami Open, and was reportedly already set to have scans on the wrist after the match against Raonic.
The injury was the central source of his frustration during Australia's recent Davis Cup loss to the United States, where he suggested Nick Kyrgios was faking illness to avoid playing the tie.
Tomic's withdrawal left Samantha Stosur as the only remaining Australian in the singles draws at Indian Wells.
Tomic said even before taking the court against Raonic that he would miss next week's Miami Open, rated in prestige behind only the year's four annual grand slam events.
Meanwhile, second seed and world No.2 Andy Murray squandered a 4-1 lead in the third set before suffering a shock 6-4 4-6 7-6 (7-3) loss to Argentina's Federico Delbonis.
The second-seeded Scotsman let his commanding lead evaporate on a warm, windy day and needed to break the 53rd-ranked Delbonis in the 12th game just to force the tiebreaker, which the Argentine won despite dropping the first two points.
Delbonis took advantage of a series of Murray errors to run off the last five points of the decider to end the two-hour, 46-minute struggle in Stadium 1.
"Thanks to everybody here for such an amazing match. It was a very intense match , very passionate, I think," the Argentine said.
Delbonis, who reached quarter-finals this year in Rio and Sao Paulo, varied his strategy against Murray and took advantage of some weakness in the Scot's serve.
Murray failed to register a single ace and won less than 50 per cent of his second serves.
"I know it was a challenge," said Delbonis. "I have to mix (my shots) all the time.
"In the end, I can do my job and this is what I get."
It was a short appearance in only the second tournament of the year for Murray, who lost in the final of the Australian Open to world No.1 Novak Djokovic.
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