Los Angeles - Juan Martin del Potro said on Wednesday he won't defend his Indian Wells ATP Masters title, another setback in the Argentinian's comeback from a broken right kneecap.
"I am truly disappointed that I will not be able to return to the BNP Paribas Open to defend my title," Del Potro said in a statement issued through tournament organisers.
"It is one of my favourite tournaments, and I have incredible memories from last year, but my doctors have advised me to rest."
Del Potro, ranked fourth in the world, reached the quarter-finals of the hardcourt tournament in Delray Beach, Florida, last week, his first event since he hobbled out of the Shanghai Masters in October.
He was clearly less than 100 percent in falling to 84th-ranked American Mackenzie McDonald, and hours after the match announced he wouldn't defend his title in Acapulco this week.
His place in the Indian Wells draw will be taken by Japan's Taro Daniel.
"I fully understand how difficult it can be to deal with injuries, and that coming back from them is not always a straightforward process," said Indian Wells tournament director Tommy Haas.
"We wish Juan Martin all the best in his recovery, and hope to see him back at the BNP Paribas Open next year."