Big-serving South African Kevin Anderson has been ruled out for at least four weeks after undergoing surgery to repair his right elbow.
The world number 31 enjoyed a breakthrough run at the Australian Open last week, reaching the fourth round for the first time with a win over Fernando Verdasco.
Anderson's run was eventually ended by Tomas Berdych on Sunday and he has since revealed that he played through the pain barrier in Melbourne after suffering an injury earlier this month at the Sydney International.
He said: "Today I am undergoing a straightforward procedure to remove some loose bone fragments from my right elbow which were discovered by MRI diagnosis during the Sydney International.
"The fragments need to be removed to protect against the possibility of future serious injury. The procedure is common among tennis players and the recovery time is estimated at 4-6 weeks.
"Unfortunately I will have to withdraw from the San Jose and Memphis ATP events and my hope is to be fit and ready to defend my title in Delray Beach at the end of February."
The 26-year-old will come close to beating his career-high ranking of 28 following his run to the last 16 at Melbourne Park when the statistics are updated next week.