Padraig Harrington is planning to take a break from working with his current coach Bob Torrance.
The former major winner has been struggling in recent years and has not claimed a tournament win in Europe or the US since lifting the USPGA trophy in 2008.
The 39-year-old said: "I've got to change something in myself, attitude or something like that.
"We haven't split. Until I am ready to listen to what he has to say we are having a break."
Torrance is one of the most well respected coaches in the game and has worked with Harrington for the last 15 years.
He said he was shocked by the announcement and said Harrington was "like a son to him".
Harrington has dropped down the rankings in recent months and is now languishing at 64 just two years after he peaked at word number three.
The Irishman failed to make the cut in the recent Irish Open and said he was frustrated by the lack of progress he has been making with his game.