By GREG BEACHAM ,  AP Sports Writer

RANCHO MIRAGE, Calif. (AP) — Lexi Thompson heard fans chanting her name as she approached the 18th green, and it moved her to the brink of tears for the second time in an hour.
Although she had lost her big lead at the ANA Inspiration on a four-shot penalty for a day-old rules violation , Thompson had gained the unabashed support of a crowd desperately willing her to overcome this bizarre break.
Instead, So Yeon Ryu seized her opportunity to win the LPGA Tour's first major of the year when she birdied the only playoff hole Sunday.
Thompson had to settle for second place, a check worth roughly $155,000 less — and widespread sympathy as the latest golfer to get blindsided in a major by the peccadillos of this fussy, fastidious sport.
"It's great to have the fan base that I do, and they really got me through the whole round," Thompson said. "It's unfortunate what happened. I did not mean that at all. I didn't realize I did that. I fought strong through the finish, and it was great to see the fans behind me."
The fans on the Dinah Shore Course largely shared the mixture of bewilderment and anger expressed by Thompson's fellow golfers and most viewers online.
The 22-year-old U.S. Olympian is the third major contender to be hit with a perplexing penalty for a violation of golf's stringent rules in the past year. The decision reignited the debate about this sport's baffling willingness to allow armchair refereeing — and renewed hope for common-sense rule changes that could be adopted as early as 2019.
"Viewers at home should not be officials wearing stripes," Tiger Woods tweeted. "Let's go @Lexi, win this thing anyway."
Thompson was penalized for marking and moving her ball less than an inch before a 1-foot putt on the 17th green during her third round at Mission Hills Country Club on Saturday. After putting down a marker and picking up the ball, Thompson swiftly put it back — but not precisely in the same place, video review showed.
The minor action went unnoticed live, but a television viewer spotted it and emailed tour officials while Thompson was playing the front nine on her final round with Suzann Pettersen on Sunday.
After nearly two hours of agonizing over video of the moment, LPGA Tour rules official Sue Witters got the unpleasant job of informing Thompson about her penalty after she left the 12th green.
"Is this a joke?" Thompson asked.
Even Witters understands the prevailing opinion about the ruling.
"Sure, but what's my choice?" she asked. "(Allow) a violation in the rules, and then it would be the opposite story: 'Oh, they knew. Why didn't they do anything about it?' I can't go to bed tonight knowing that I let a rule slide.
"It's a hard thing to do, and it made me sick, to be honest with you."
Sickening things have happened with regularity in majors lately.
At the men's U.S. Open at Oakmont last year, Dustin Johnson won despite playing the last seven holes without knowing his score. His ball had moved slightly while he lined up a putt on the fifth green, the USGA eventually hit him with a one-shot penalty after his round.
A few weeks after that at the U.S. Women's Open , Anna Nordqvist got a delayed two-stroke penalty during a three-hole playoff for accidentally touching the sand with her club in a bunker when a television cameraman spotted it. Brittany Lang won by — you guessed it — two shots.
Perhaps all of this drama only underlines the importance of what could soon happen to that centuries-old rulebook.
The two governing bodies of golf released a draft of modernized rules last month, attempting to simplify the arcana. The numerous proposed changes would eliminate some of the punishment for inadvertent mistakes and freak occurrences that don't actually give an advantage to a competitor.
But those changes haven't been adopted yet, and Thompson was left with a crushing penalty for an action that easily could have been ignored under a more pragmatic interpretation of intent — a "reasonable judgment standard," under the proposed rules.
Instead of losing her composure after the ruling, Thompson incredibly birdied the next hole, burying a 25-foot putt. She made two more birdies and a bogey down the stretch, but missed a 15-foot eagle putt to win it on the last hole of regulation.
Ryu nearly put her playoff approach shot into the water, but got up and down with a 6-foot birdie putt to win. Her celebration was understandably muted, but she still took the traditional leap into Poppie's Pond.
A few yards away, Thompson embraced her family and later signed dozens of autographs. She was shaken, but not deterred.
"Every day is a learning process," Thompson said. "I wasn't expecting what happened today, but ... it happens, and I'll learn from it and hopefully do better."