Shin-Soo Choo was 18 years old and fresh off his MVP performance for South Korea in the World Junior Baseball Championship when he signed with the Mariners and came to the United States. A product of a baseball-focused high school academy in his native land, he was no stranger to the game, but quite literally everything else -- the culture, the food, the language -- was new to him.

"For me, seven years in the Minor Leagues, I learned a lot," Choo says now. "Not just baseball but how you deal with teammates and with coaches. Everything. I wouldn't do anything differently."

But more recently, a new crop of South Korean-born players have immigrated to Major League Baseball in a different and more direct way.

Hyun-Jin Ryu's initial success with the Dodgers was important. But Jung Ho Kang's stellar, albeit injury shortened, rookie year with the Pirates after nine seasons in the Korean Baseball Organization was the true game-changer that has legitimized the jump straight from KBO to MLB and opened the door for others.

You saw it most prominently over the offseason with the Twins' $24.8 million total investment, between the posting fee and four-year contract, in slugger Byung Ho Park, who will be their designated hitter. But the Orioles have also extended an opportunity to Hyun Soo Kim in their outfield. And the Mariners, with first baseman Dae-Ho Lee, and the Cardinals, with reliever Seung Hwan Oh, have taken chances on Korean-born players who spent the bulk of their international careers in the KBO before more recently shifting to the Nippon Professional Baseball league in Japan.

If any or all of these players catch fire the way Kang did, look out. Korea could become akin to Cuba, in terms of the resources and dollars clubs will be willing to commit toward its talent.

"We saw this with Cuba once Alexei [Ramirez] came over," says A's general manager David Forst. "Once players come over and have success or don't, you have a better understanding of the data and the comparisons. So when Kang comes over and does well, all of a sudden you've got a huge datapoint there to judge everybody else in that league by. It gives you a lot more confidence in what they're doing."

A National League scout who makes multiple trips per year to the Pacific Rim estimated that there are probably eight to 10 teams currently devoting significant scouting resources to the KBO. Much like the posting fee for Park ($12.85 million) escalated in the wake of what Kang ($5 million) did in '15, that number will undoubtedly expand if Park or the other prove to be legitimate big league players.

But the "if" above is a big one, because Kang's datapoint could very well prove to be an outlier. Scouts still don't always know what they're watching in Korea.

"When you scout a Major League game, there are probably 10-20 plays that are critical from a scouting perspective, like a ball in the gap that a guy's got to make a play on or an 0-2 count when a hitter is facing a nasty slider," the NL scout explains. "In Korea, you might have five to 10. So you've got to be honed in to catch those moments."

The industry opinion, at the moment, is that the KBO lacks the depth of the NPB, especially on the pitching side. The average velocity a Korean hitter faces is nowhere near what it is at the big league level, so those true evaluative moments are few and far between.

"There is that debate of, 'What is Korean baseball?'" says Cardinals GM John Mozeliak. "Is it Double-A, Triple-A, Four-A? I do think that's everybody's internal question. We're trying to look at it in a way to prove performance from there to here. I think the scouts are still battling that as well."

Right now, in O's camp, Kim is battling it. His initial exposure to big league ball began with an 0-for-23 stint in the Grapefruit League, though he's shown signs in recent days that he's acclimating to the environment.

"The pitchers are throwing harder than the Korean pitchers," he says through an interpreter. "So I'm getting used to seeing those pitches and reacting to them."

Kim had a reputation as the best pure hitter in the KBO, where he had a .406 on-base percentage over 10 seasons. But a scout who saw Kim overseas noted that a rare meeting with 93-mph heat, middle-in, in one game last season got Kim's feet moving in the box.

That's a red flag in MLB, where the average fastball velocity last season was 92.4 mph. It could affect Kim's viability as an everyday player.

And on that note, there is this other factor to consider: The KBO is a six-day-a-week league, with Mondays off, except in the event of late-season make-up games.

"That's the biggest adjustment," says Kim, "getting ready to play every day."

But Kang, who had a .287/.355/.461 slash line and established himself as an everyday infielder on a playoff team before a Chris Coghlan slide injured his knee and fractured his leg last September, adjusted just fine.

"Experience is the most important thing, whether you're in KBO or MLB," Kang says. "If you're exposed to great experiences, you'll be a great player."

Though Spring Training stats are always meant to be taken with a grain of salt, Park has settled in seamlessly with the Twins, entering the week with three homers, including a grand slam.

"I haven't really seen him overmatched," manager Paul Molitor told reporters.

And though the 33-year-old Lee was something of a curiosity, given his age and his size (he's listed at 6-foot-4, 250 pounds), he might just be winning a spot on the M's Opening Day roster with his professional approach at the plate (he had only two strikeouts in his first 25 at-bats) and power stroke. Oh, who came equipped with the excellent "Final Boss" nickname, is assured a spot in the Cardinals' bullpen, and there is some inter-organizational thought that he could possibly wind up fulfilling the closing duties on days Trevor Rosenthal needs a break.

There are a lot of eyes on these guys. Most notably back home, where more big league fates could reside on 2016 outcomes.

A scout affiliated with a KBO team listed two hitters (Jae Gyun Hwang and Ah Seop Son) and three left-handed pitchers (Kwang Hyun Kim, Hyeon Jong Yang and Woo Chan Cha) as strong possibilities to garner interest next winter, especially in a class that looks to be light on NPB free agents. Kim and Yang were posted after '14, but the Padres and Kim could not come to terms on a contract and the Kia Tigers rejected the highest bid for Yang.

Because of the increasing interest in Korean talent, there is talk in the industry of a potential cap (an $8 million figure has been floated) on future KBO posting fees.

"Japan just has way more depth and is still a better game," the NL scout says. "The difference for me is the Korean game is more similar to our game, in terms of approach -- more reliance on power, less reliance on small ball. So this is a transitional time. Korea used to be a market just for amateur guys -- Choo and a few scattered pitchers. Now, it makes more sense for a player to stay there and play for eight to 10 years and then transition while in their prime physical peak."

Choo wouldn't change his personal path. But he's glad the bridge has evolved for others.

"I'm happy to see them here, and I hope more players come," he says. "Everybody wants to be in the Major Leagues. We go a different way, but we finish in the same place."


Anthony Castrovince is a Sports on Earth contributor, columnist and MLB Network contributor. Follow him on Twitter @Castrovince.