The world golf number two Phil Mickelson doesn't believes his arthritis will afect him too much at this weekend's US PGA Championship in Milwaukee.
Mikelson revealed he has been diagnosed with a severe form of arthritis that left him unable to even get out of bed.
The reigning Masters champion says doctors at the Mayo Clinic in Minnesota are treating him for psoriatic arthritis which first flared up in the week prior to the US Open in June.
The left hander says he feels the disease is under control and he feels 90 per cent fit.
If he goes ahead, as expected, and competes this week, Mickelson could surpass Tiger Woods for No.1 ranking with a strong performance at the final major championship of the 2010 season.
The left-handed American had a chance to overtake Woods last week but still feeling the effects of his newly-diagnosed disease stumbled to a final round 78 at the World Golf Championships Bridgestone Invitational.