MARANA, Ariz. (AP) — Phil Mickelson played a practice round at Pebble Beach on the Saturday before the U.S. Open and was walking back to his car when he felt pain in his ankle, hip and even his finger. it was uncomfortable, but no great cause for alarm.

“I thought it might just be wear and tear of the joints over the years,” he said.

The scare came a week after the U.S. Open during a family holiday in Hawaii when the pain returned.

“I went and laid down on the couch, and it hurt so bad to move,” Mickelson said. “Thereafter, I went to try to play golf and the pain had gone to my shoulder. I couldn’t take the club back halfway. And I was concerned about the impact on my golf career.”

Mickelson was lucky to detect it early.

He immediately saw a rheumatologist in San Diego, then went to the Mayo Clinic for a second opinion. Both agreed that he had psoriatic arthritis, an autoimmune disease that causes pain, stiffness and swelling around the joints.

Mickelson was able to get on a treatment plan, and he felt good enough to resume his full workouts by November.

But it left a lasting impression, and now Mickelson wants to do his part to help educate others about the disease.

Mickelson has created a partnership with Amgen and Pfizer, inc. and will launch a public awareness campaign Wednesday called “On Course with Phil.” The idea is for people with psoriatic arthritis, rheumatoid arthritis or plaque psoriasis to have it diagnosed early and get on a treatment program that’s best for them.

The three-time Masters champion has not signed any endorsement deal, and he said it will not be visible on his bag or other attire. There were will be advertising, along with a website (oncoursewithphil.com) in which people can read his story and get information on the disease, from its symptoms to finding the right treatment.

Mickelson said he lost about 20 percent of his strength, along with some swing speed. he said most of the speed has returned, and he hoped to have the rest of it back during the road to the Masters.

It cost him part of his summer, no doubt. he was never in contention at the British Open, and made his move too late to seriously contend at the PGA Championship, where he first revealed he had psoriatic arthritis. he had a chance the second half of the season to go to no. 1 in the world, but he had only one top 10 finish.

Even so, he feels fortunate it wasn’t worse.

“He was smart, the fact he recognized something was going on and sought medical attention early,” said Christopher Ritchlin of the University of Rochester School of Medicine and Dentistry, who has been studying the diseases for more than 20 years.

Ritchlin said rheumatoid arthritis can be irreversible if left untreated. As for psoriatic arthritis, he said that often gets overlooked because people do not make the connection between stiffness and swelling in the joints and flaky skin from lesions.

“It’s a common problem, and Phil can tell his story,” Ritchlin said.

He was equally happy that Mickelson helped bring together for the first time the Arthritis Foundation and the National Psoriasis Foundation to form a coalition that can educate people on the disease.

As for Mickelson?

“I’m in a good place now,” he said. “I’m able to practice and work out hard. As I’ve said, my goal is to make this year the kind of year I wanted last year to be. I also want to help other people who have situations similar to mine, because it’s very manageable.”