The 39-year-old finished in a tie-for-69th at the Players Championship in Florida, 15 strokes off the pace at TPC Sawgrass.
However, part of the reason for his rankings slump has been his lack of competitive golf during 2015, having teed-off in only four tournaments this calendar year.
His last win came in August 2013, while his most recent Major victory was seven years ago next month.
During his career he has topped the world rankings for a record 683 weeks but is now slipping down the table quickly.
In March of this year he fell outside the top 100 for the first time since the week before he claimed his first PGA Tour title during the Fall of 1996.
Rory McIlroy has stretched his lead at the summit, while Rickie Fowler is up to ninth after his dramatic win at Sawgrass.