The Royal and Ancient club secretary, Michael Bonallack, said: "We are sorry about his continuing problems but, having talked with his manager [Sergio Gomez], there is cause for optimism and we hope he will continue to improve.
"Jose Maria has tried everything to be fit in time, playing three times a week, but not on consecutive days, and after 12 or 13 holes he starts to have problems."
Olazabal, 30, was in hospital three weeks ago to have a metal staple removed from the big toe which was shortened at the start of last year. Examinations then showed that there was no deterioration in his arthritic condition.
Gomez added: "Jose Maria is continuing to make progress, but not quite enough.
"He's now missed the first three majors this year, but we won't make a decision on the fourth just yet. We have to wait and see." The US PGA championship is in Kentucky from 8 to 11 August.Reuse content