PALM HARBOR, Fla. (AP) - Retief Goosen was about ready to give up.
His lower back was in so much pain that he decided to withdraw next week from Bay Hill so he could get treatment. A double bogey late in his round knocked him nine spots down the leaderboard, which he figured was the end of his hopes to get into the Masters.
One day later, everything changed.
Goosen ran off three straight birdies on the back nine and closed with a tough par from the fairway bunker on the 18th hole Saturday for a 6-under 65 that put him atop the leaderboard with Jim Furyk in the Transitions Championship.
Goosen is No. 52 in the world ranking, and he has to be in the top 50 after next week to avoid missing Augusta National - along with St. Andrews, his favorite course - for the first time since 1999.
Or he can avoid the math and just win the tournament, which comes with an automatic invitation.
Those prospects looked dim when he decided Friday to pull out of Bay Hill, and arranged for a protein injection in Virginia on Wednesday. Suddenly, the final round is packed with significance.
``Maybe I'm fighting for that last spot in Augusta,'' he said.
Either way, it figures to be quite a battle.
Furyk, determined to overcome an atrocious season in 2011, surged into the lead with a 6-iron that covered the flag on the par-3 15th hole and settled 3 feet away for a birdie. He fell back into a tie on the 18th hole with a three-putt bogey up a steep ridge. That gave him a 66.
Furyk and Goosen, former U.S. Open champions who have won before at Innisbrook, were at 11-under 202.
``I made some birdies out of the rough today, and was able to knock some putts in and keep the round going,'' Furyk said. ``I played very patient, and when I struggled - no putts were going in - I didn't let it bother me.''
Furyk was tied for the lead with Sang-moon Bae, the South Korean rookie who lost in the quarterfinals of the Match Play Championship to Rory McIlroy.
Bae escaped with a par on the par-5 14th after his 3-wood found the water by making an 18-foot putt. He wasn't so fortunate on the 16th, however. He drove left into the trees to protect against water running down the right side of the hole. He pitched out to the fairway into the rough, flew the green and three-putted for a triple bogey.
He had at least made birdie on the 17th, and wound up with a 68.
Bae was one shot behind, along with Jason Dufner, who struggled to a 71 and hopes is worst round is out of the way as he tries to win for the first time on the PGA Tour.
Dufner tends to see the glass half-full. Even though he made three straight bogeys to lose a five-shot lead in the final hour of the PGA Championship, he thinks about the tough par he made on the 18th to at least get into a playoff that he lost to Keegan Bradley.
And even though Dufner's bogey-free streak ended Saturday on a par 5, he walked off the Copperhead Course realizing that he was only one shot behind, very much in the hunt.
``Anything can happen with as many people bunched up like that,'' he said.
Goosen started the third round five shots out of the lead and finished atop the leaderboard. There were 28 players separated by five shots going into the final round Sunday.
Ernie Els, who likely would need to win to get into the Masters, had a 68 and was only three shots behind. So was Luke Donald, who can return to No. 1 in the world by winning at Innisbrook.
Harrington has been dropping shots since his course-record 61 on Thursday. He had a 72, yet still was only four behind.
The mystery, however, is Goosen.
He has a bulging disk and a degenerating disk in his lower back, which forced him to miss two majors last year. Kicking a soccer ball with his son last month caused it to flare up again, and the pain has been getting worse. What has saved the South African this week is the warm weather, and a few adjustments in his stance to help get through the ball.
``It's not good,'' Goosen said.
He plans to get a protein injection in his disks on Wednesday in Virginia, similar to the treatment that Vijay Singh and Fred Couples have received in Germany. Goosen's pain was so bad last year that his left leg went numb when he stooped over, and he started to put 90 percent of his weight on the right side.
He has lost length off the tee, which isn't as big of a factor at Innisbrook. He atoned for that with his putting, which has carried him two a pair of U.S. Open titles over the years.
``The last three weeks, it's really just started getting bad again,'' Goosen said. ``So hopefully, I'll be ready to get going again after the Masters - or maybe the Masters, if I play well tomorrow.''
Furyk won the Transitions two years ago, part of a big year that ended with a $10 million bonus for winning the FedEx Cup. He hasn't won since then, and Furyk said he had no one to blame but himself for falling out of the top 50.
He couldn't wait for last year to end, though it finally did on a happy note. He shot 69 the last day at Sherwood for a tie for sixth, earning just enough points that he finished the year at No. 50 by two-hundredths of a point. That at least made him eligible for the Masters, though Furyk hasn't had to worry about qualifying for majors for some 10 years.
His long offseason - Furyk didn't return until Pebble Beach - allowed him to clear his head, and he also sorted out some equipment.
``My results probably don't look good on paper, but I feel good about the way I'm playing,'' Furyk said. ``I've been playing much better golf this year than I was last year.''
DIVOTS: Stewart Cink had a hole-in-one on the par-3 eighth, notable in that he said he also made an ace on the same hole 10 years ago ... Nine of the 20 players separated by four shots going into the final round are not eligible for the Masters. A win comes with an automatic invitation. The group includes Chris DiMarco and former PGA champion Shaun Micheel.