Tiger Woods said he did no more damage to his left leg at The Players Championship last weekend and hopes to play at the US Open next month.
Woods played only nine holes - his shortest tournament - when he withdrew because of what he described as a "chain reaction" of pain from his left knee to left Achilles tendon and tightening in his calf. He shot 42 on the front nine.
On his website, Woods said he irritated the knee and Achilles without making them worse.
He said doctors have advised rest, cold-water therapy and soft tissue treatment, which he said he already had been receiving.
"Aggravating my injury is very disappointing," Woods said. "I'll do whatever is necessary to play in the US Open, and I'm hopeful I can be there to compete."
The US Open takes place from June 16 to 19 in Bethesda, Maryland.
A posting on his website said Woods was doubtful to play at the Memorial Tournament, which begins on June 2, while he tries to strengthen his leg.
Woods reported a mild sprain of the medial collateral ligament and a mild strain of his Achilles from hitting a shot on the 17th hole during his third round at the Masters last month.
He said he did not play any golf until the Monday of The Players. Woods looked fine during the nine-hole practice rounds he played last week, and Sean Foley, his swing coach, said he was pleasantly surprised to see Woods look as though he had not lost much from when he had last played in the Masters.
Woods said he hurt himself on the opening tee shot at Sawgrass.
"The knee acted up, and then the Achilles followed after that, and then the calf started cramping up," Woods said after he withdrew. "Everything started getting tight, so it's just a whole chain reaction."