The 1999 Open winner has dropped to 424th on the world rankings from a high of 26.
"I hate the position I'm in," the Aberdonian told BBC Scotland. "I don't like not being a good golfer.
"I've been putting off an operation on my foot for about four or five years now and I'm going to go in and get it done this winter."
Lawrie explained that he has a bone spur and cist on his foot.
"Once I hit 100 balls, my foot is in total bits and I can't handle any more," the Scot revealed. "My game is not in the best of states.
"I'm going to go in, get it done and hopefully next year I'll come back a little stronger.
"I'm going to bite the bullet and it's going to be a couple of months recuperating with it.
"I want to be up there. I want to be challenging and I've had a few bits and pieces in the last few years that have stopped me.
"It's just so difficult when you've got an injury and you're playing against these guys who are all younger, all fitter, all stronger, all hitting it past you but you still feel competitive."
Lawrie, who is a vice-captain with the European Ryder Cup team, will be at Castle Stuart this week for the Scottish Open, which acts as a dress rehearsal for the Open at Troon.
"I can't wait," he added. "Castle Stuart has been a brilliant venue in the past.
"The thing a lot of players didn't want was to be battered on a golf course that was mega-tough before the Open.
"They didn't want their swing wrecked and Castle Stuart is just perfect.
"You want it to blow round there and be a challenge, but you don't want it to be silly tough before you go into the Open."

The Medical Research Council team showed severely damaged organs in mice could be restored to near-normal function.
They say the findings, published in Nature Cell Biology, could eventually help people stuck on a waiting list for a transplant.
Further tests are now taking place with human tissue.
The liver does have a remarkable ability to heal itself. Even if half of the organ is removed, it can grow back.
The team, based at the University of Edinburgh, has been investigating the regenerative potential of the liver.
Normally, the main type of cell in the liver - hepatocytes - is able to restore the organ.
But one of the researchers, Prof Stuart Forbes, said: "The hepatocytes normally divide beautifully, but eventually they give up that ability to keep dividing, they become senescent, and that is something we see in all forms of severe liver injury."
So the Edinburgh team turned to a closely related group of stem cells from the biliary duct.
Injecting these cells into damaged mouse livers led to near compete regeneration.
Prof Forbes added: "The big aim would be to develop a clinically applicable cell therapy for patients with severe liver failure where transplantation is not an option."
The team say tissue from livers unsuitable for transplant could be a source of these cells.
However, Prof Forbes said liver transplants would remain the main option for patients and encouraged people to join the donor register.
Further studies will now focus on repeating the results with human tissue.
Dr Rob Buckle, the director of science programmes at the Medical Research Council, said: "This research has the potential to revolutionise patient care by finding ways of co-opting the body's own resources to repair or replace damaged or diseased tissue."
Paul Lawrie hopes foot surgery this winter will help breathe new life into his golfing career at the age of 47.
[NEXT_CONCEPT]
Transplanting cells into livers has the potential to completely regenerate them, say scientists.