The sport has been on the wane for many years in the United States island commonwealth that has produced such Hall of Famers as Roberto Clemente, Orlando Cepeda and Roberto Alomar.
You wouldn't know it by the way the Puerto Ricans have performed in the World Baseball Classic, though.
Chicago White Sox right fielder Alex Rios hit a two-run home run, and career minor-leaguer Mario Santiago pitched 4 1/3 outstanding innings before leaving with an arm injury as Puerto Rico ended Japan's reign as WBC champions with a 3-1 victory Sunday night at AT&T Park.
Puerto Rico advances to Tuesday's championship game. The Dominican Republic and the Netherlands meet Monday night in the other semifinal.
Japan will not win the WBC for the first time. The Japanese captured the inaugural event in 2006 and successfully defended their title in 2009.
There were just 11 Puerto Rico natives on Opening Day rosters in the major leagues last season. The nation's winter league has long been plagued by poor attendance, and there has been talk about it potentially folding.
Puerto Rico made it out of the first round of the WBC for the first time before advancing all the way to the title game. Manager Edwin Rodriguez is hoping that will spark interest in baseball among youths on the island.
"Obviously we're thinking about winning everything, but we mainly talked when we first got together about going out there and playing the right way, because everybody was watching in Puerto Rico," Rodriguez said before the game. "The last 10 or 15 years, Puerto Rican baseball had been a little bit down. I think that a good performance from the team in this tournament will put Puerto Rican baseball back on the map. And I think we already accomplished that."
And if Puerto Rico had not accomplished that before Sunday night, then it certainly did after stunning Japan.
"This is huge," Rodriguez said. "It's a huge accomplishment not only for our players but everyone in our country. A lot of people are watching back in Puerto Rico, and I know they have to be very proud. It's a very emotional thing."
Santiago, the only player in Puerto Rico's lineup without major league experience, retired the first 10 batters he faced before Hirokazu Ibata grounded a single up the middle with one out in the fourth inning.
Santiago, though, was pulled from the game with tightness in his right forearm with one out in the fifth inning after pitching coach Ricky Bones came to the mound along with an athletic trainer. Santiago had thrown 61 pitches, far short of the limit of 95 imposed on the pitchers in the championship round.
Jose De La Torre entered with a runner on second, and he walked Sho Nakata before bouncing back to strike out Atsunori Inaba and Nobuhiro Matsuda to escape the jam and preserve Puerto Rico's 1-0 lead.
Santiago, who signed a minor league contract with the Los Angeles Dodgers in the offseason, allowed two hits in his 4 1/3 scoreless inning while walking one and striking out two.
Santiago credited the pitch-calling of catcher Yadier Molina, the Gold Glove winner from the St. Louis Cardinals.
"I follow his lead," Santiago said. "He is the best catcher in baseball. I have total faith in whatever sign he puts down."
Santiago pitched in the Kansas City Royals' farm system from 2005-11, reaching as high as Triple-A, then spent last year in Korea. He made the Puerto Rican pitching staff despite posting an 8.64 in 16 2/3 innings for Carolina in the Puerto Rican winter league in the offseason.
Rios gave Puerto Rico some cushion when he hit a towering two-run home run into the left field stands in the seventh inning to make it 3-0. Cleveland Indians infielder Mike Aviles singled to lead off the inning, and Rios followed by going deep against Atsushi Nohmi, who led the Japanese Central League with 172 strikeouts last season for the Hanshin Tigers.
Rios had been 3-for-24 with no RBI in the tournament when he stepped up in the seventh.
"He had thrown me a changeup earlier in the at-bat, so I had the chance to see the pitch once," Rios said. "He threw it again, and I took a good pass at it. It was a very exciting at-bat. It gave us a three-run lead, and I felt good about our chances with a three-run lead in the seventh inning."
Japan scored its run in the eighth when Takashi Toritani tripled and scored on Ibata's single to right. The Japanese had a chance for more before they were stymied by a combination of bad baserunning and veteran left-handed reliever J.C. Romero.
Romero was called on to face cleanup hitter Shinnosuke Abe with one out and runners on first and second. Seiichi Uchikawa took off from first base while Ibata stayed at second on a botched double steal, and was Molina easily threw out Uchikawa.
"There was a sign that the double steal be attempted, and Ibata's start was a little delayed, and that is what happened," Japan manager Koji Yamamoto said through a translator. "It was unfortunate, but our players, all of them, worked real hard."
Fernando Cabrera got the final two outs for the save.