KBO League closer Woo-seok Ko, 26, has become a major leaguer.
San Diego officially announced the signing of Ko on Thursday. The contract is for two years and $4.5 million guaranteed. It includes a one-year mutual option. After two years of performance-based options, the deal will be worth $3 million in 2026, with a $2.4 million bonus for the third year, subject to a player option. Not bad for a bullpen arm in the major leagues.
Just a few days ago, most people were wondering if Ko would be able to make it as a major league pitcher, but major league veterans are hopeful that it’s possible.
Former KIA pitching coach Seo Jae-heng, a first-generation Korean major leaguer, said, “When Oh Seung-hwan went to the U.S., they said it was not easy to take only fastballs. His fastball was huge, but he succeeded by throwing a sweeper-type changeup. Now, I think Go Woo-seok’s overall pitch value has risen to about A-grade. His fastball is really good and his slider has a very good angle,” he said.
Oh Seung-hwan, who came to the U.S. as a closer before Ko, also said, “I think the chances of success are very high. I think it’s a lottery ticket that hasn’t been scratched. I think it’s a lottery ticket that hasn’t been scratched. If he goes to the U.S., there might be more redemptions.”
Oh Seung-hwan said Go Woo-seok needs to be confident with his changeup. “People don’t realize it, but his changeup is really good. People only pay attention to his fastball, but I think his curve is in the top few percent in the major leagues,” Oh said. He added, “Of course, the fastball is his pride. But in the major leagues, I don’t think it’s necessary anymore. My first priority is to face hitters, not to show my pride. I have a good changeup, so I don’t think I need to doubt myself.”
Samsung pitching coach Jung Min-tae, a KBO legend and pitching expert who also played overseas in Japan with Yomiuri, also took note of Go Woo-seok’s changeup.
“His fastball is said to be fast, but it’s average in the United States. He needs to utilize his changeup better. The angle of his curve is pretty good, so utilizing it is the key.
If he throws that much as a middle reliever in San Diego, he will be able to achieve successful results.”
It will be important to see if Go’s “mentality,” which has been proven to be successful as a closer in the KBO, can hold up in the United States. In San Diego, where the closer’s spot is vacant, Ko will have to compete.
“In America, they don’t say anything negative at first. They say you’re good and give you positive reactions, but the first time you get hit, the reaction of your surroundings, the media, and whether you can get up right away is the difference between success and failure. That’s why mental strength is important, and I’ve seen that Go Woo-seok’s mental strength is never weak.”
Oh Seung-hwan has a different perspective on the impact of the position. “Maybe the Japanese pitcher (Matsui) has a relatively good contract (five years, $28 million), so he will definitely get more opportunities. But that can be overturned by Woo Seok-i showing three months. “When you’re paid a lot of money and you start out as a closer and you blow a couple of saves, you can lose confidence. But he’s probably not going to be a closer at first. If he goes out in the middle innings, he’ll be able to throw more comfortably, and that will give him time to adjust to the closer’s role.”
Seung-hwan Oh has been there. Oh joined the Cardinals in 2016 with specialty closer Trevor Rosenthal and started as a middle reliever before being promoted to the closer role midway through the season, finishing with a 6-3 record, 19 saves and a 1.92 ERA in 14 appearances.Oh said, “Going with my family and how well (Lee) Jung-hoo will help me, that’s really big. I think it’s a happy move,” he said. “I think he can be a top-notch bullpen pitcher in the major leagues if he shows well in the beginning. I think San Diego is the winner for acquiring Go Woo-seok.”