Rory McIlroy has been knocked out of the world's top 10 following his dismal showing at the WGC-CA Championship.
The 20-year-old Northern Irishman, ninth on the rankings entering the event, finished joint 65th of the 68 players.
He drops to 11th on the new list after being overtaken by Doral winner Ernie Els and Padraig Harrington, who came joint third.
"I just didn't have it and haven't had it for the last couple of weeks", McIlroy said on Sunday.
"I've a few issues to sort out when I get home.
"The back isn't worrying me, but it's getting me down."
He intends to ease off on the physio work, at least for a while, saying:
"Half of it is probably mental. I'm starting off in a negative mood."
Hopefully, a trip to Augusta these next three days will get him in a better frame of mind.
On Sunday, Harrington fell out of the reckoning with a hat-trick of bogeys from the 13th and after his level par 72 on a day of low scoring stated:
"I obviously struggled a bit all day.
"Those three holes were pretty simple up and downs and I didn't make them.
"I was hanging on a knife-edge all day, but I learnt a few things - as you always do in these situations.
"My bunker play was just not with it and my pitching could have been a bit better. You don't really see it until you are under pressure.
"I'm happy - I need to be competing and testing myself."
Northern Ireland's Graeme McDowell matched Els' 66 to climb from 16th to joint sixth with England's Paul Casey, Spaniard Alvaro Quiros, American Bill Haas and little-known Australian Alistair Presnell.
"I never thought for one second I could get into the hunt, but this is a great boost for me," said McDowell, who had been in danger of falling outside the world's top 50 entering the second world championship of the season.
Casey has now finished second, fourth and sixth in his last three starts in America, but is really keen to start winning again after hearing that television commentator Johnny Miller had called him "the bigger under-achiever" in golf.
Ian Poulter, who beat Casey in the final of the World Match Play last month, gave his confidence another shot in the arm with a closing 64, the joint best round of the tournament.
He was still only 37th, but having suffered a back strain on the eve of the event he was delighted the week was not a total write-off.
© Press Association