Tiger Woods is making gradual progress in his recovery from back surgery, but cannot set a date for his return to the golf course.
Woods underwent an operation at the end of March after struggling for several weeks with a pinched nerve in his back.
The normal recovery time for the injury is three to four months, but Woods will not rush his rehabilitation and is yet to take a full swing with a club.
"I'm doing everything I can and listening to my doctors and working on a strength programme, and then we just have to see how my back is," he wrote on his official website.
"Some people heal up in three months, some people take four months, some people take longer. I just don't know.
"I haven't used a sand wedge yet. I've just done putting and chip-and-runs using the same length of motion. I haven't really rotated yet.
"As far as taking a full swing, I have conference calls with my doctors every couple of weeks to see how my progress is and just kind of chart it out from there."
The 38-year-old American has worked diligently in the gym during his career and believes his body will respond well to treatment.
"My recovery from microdiscectomy surgery for a pinched nerve in my back is coming along, but it's a very slow process," he continued.
"I'm still sore. Not from the procedure itself but the incision. I just need to get back to my day-to-day activities, and that's it.
"One reassuring thing from my medical exam is I have zero arthritic changes whatsoever. I've kept myself in very good shape over the years, and it has paid off.
"We knew going into this procedure that it really helps to be strong, especially in my glutes and my abs. I was strong in both departments, and that helps with the recovery and rehab, and you're able to come back faster."
This latest fitness problem has prevented Woods from defending his title at the Players Championship this week.
He is unsure whether the surgery will restrict his game, but is remaining upbeat after overcoming previous injuries.
"Once I begin swinging a club again, I'm not sure if I will have to make any changes to protect my back; that's up to (coach) Sean Foley and me on what we do," he said.
"As far as limitations, it's a building process, just like when I came back from my knee and Achilles injuries.
"You start from the green and work your way back: putting, chipping, pitching, wedging, mid-irons, long irons, woods and eventually playing. That's all a process and takes time.
"We have to make sure my back heals fine and I have the strength and mobility going forward.
"As I've said several times, I hope to be back sometime this summer, but I just don't know when."