PALM HARBOR, Fla. – Louis Oosthuizen was worried about his back after losing in the quarterfinals of the WGC-Accenture Match Play Championship to eventual winner Jason Day.

He's not out of the woods yet, though he was pleasantly surprised by how he felt at Doral last week.

Oosthuizen, whose back injury caused him to withdraw from two majors and not play a third one last season, said tests have revealed disk problems in the L-5 and S-1. He had two cortisone injections during his week off between the Accenture Match Play and Doral.

Of greater concern is practice.

Oosthuizen said he has only been able to warm up for about 30 minutes before each round. Even with arguably the sweetest swing in golf, ''You can't be consistent with your swing if you only do that,'' he said.

''But it's a lot better,'' he said. ''And that's a good sign.''

Oosthuizen is playing this week in the Valspar Championship.

MASTER PLAN: Roberto Castro, who went to Georgia Tech, played four rounds at Augusta National before he qualified for his first Masters this year.

He already has played twice in the fall, and plans two more rounds during the week of the Valero Texas Open.

How many times can he go before the Masters?

''Within reason,'' he said with a smile. ''They have been very nice to host me.''

He last went with Chris Kirk, who also lives in Atlanta, the week of Thanksgiving. The Eisenhower Tree was still standing, which Castro said presented a problem because he tends to hit a fade off the tee. What he remembers more is playing the championship tees on a cold, soft day.

''When the ball backs up in the fairway, it's like the longest course in the world,'' he said.

GRADUATION DAY: Even though he is coming up on the one-year anniversary of turning pro, Hideki Matsuyama of Japan already has played in all four majors and every World Golf Championship. As a PGA Tour member, one tournament he looked forward to playing was the Arnold Palmer Invitational at Bay Hill.

That will have to wait.

The 22-year-old Matsuyama headed home after Doral for a big occasion. He's graduating from college.

Unlike Ryo Ishikawa, who turned pro as a teenager and played big events while working on a high school diploma, Matsuyama went to college and pursued his degree while competing against the world's best. His field of study was social welfare.

Asked if he was excited to graduate, Matsuyama smiled and said, ''I'm more excited about playing here in America.''

He won't play again until Augusta National, which makes him unusual in one respect. It takes most people at least one full year to go from a college degree to a Masters. For Matsuyama, it will only be a few weeks.

NEW SPONSOR: The LPGA Tour is off to a good start even before it starts its domestic schedule next week. JTBC, a leading broadcasting company in South Korea, has agreed to be the title sponsor of what now will be the JTBC Founders Cup in Phoenix.

The tournament is next week at Wildfire Golf Club.

JTBC is an affiliate of J Golf, which recently signed a contract extension with the LPGA Tour. Along with being a title sponsor in Phoenix, JTBC will be presenting sponsor at three other LPGA events this year. Those four events will be shown on JTBC's network, which is distributed to more than 21 million households in Korea.

Its first order of business for the Founders Cup was to give sponsor exemptions to Cheyenne Woods and former U.S Women's Open champion Birdie Kim.

DIVOTS: Patrick Reed (twice) and Ryan Moore are the only players to go wire-to-wire, including ties, in 16 stroke-play events on the PGA Tour this year. ... Derek Fathauer, who missed the cut last week in Chile, shot a 59 during a practice round for the Web.com Tour event in Brazil on Tuesday. ... Minjee Lee of Australia, the No. 1 amateur in the world, was among nine amateurs awarded exemptions to the Kraft Nabisco Championship on April 3-6, the first LPGA major of the year.

STAT OF THE WEEK: Tiger Woods earned $82,194 in his first three PGA Tour events as a pro in 1996. He has earned $86,919 in his first three PGA Tour events this year.

FINAL WORD: ''There are pretenders on Sunday, contenders and closers. The rarest of all golfers are closers that can actually win tournaments, not win by accident because of other people falling apart.'' – Johnny Miller

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