Riley Thompson was a member of the Chicago Cubs organization for seven years, but never reached the major leagues. Two years after leaving them, however, the right-handed pitcher has established himself as one of the best pitchers in South Korea.
Now in his second season with the KBO League’s NC Dinos, Thompson has taken a significant step forward in 2026. Through 17 starts, the 30-year-old is 6-1 with a 2.92 ERA, 1.04 WHIP and 132 strikeouts across 101.2 innings. Opposing hitters have batted only .212 against him, and 11 of his 17 starts have qualified as quality starts.
Those numbers put Thompson among the KBO’s elite. Among pitchers who have thrown at least 100 innings, his 2.92 ERA ranks fourth in the league, behind only Gwak Been, former Texas Rangers lefty Wes Benjamin and Choi Min-seok. His WHIP is lower than all three of them, and only three qualifying pitchers have allowed fewer than 3.50 earned runs per nine innings.
Thompson has been even more impressive in the strikeout column. His 132 strikeouts rank fifth in the KBO despite him having thrown considerably fewer innings than any of the four pitchers ahead of him. League leader Been has 169 strikeouts in 141 innings, while Thompson has reached 132 in only 101.2, with his 11.69 strikeouts per nine innings comfortably exceed Gwak’s 10.79. And although it is taking place in Korea, Thompson’s performance is nevertheless is a considerable turnaround for a pitcher whose career in the United States had stalled.
Thompson’s Cubs Career
The Cubs selected Thompson in the 11th round of the 2018 MLB Draft out of Louisville, although they were not the first organization to do so. The Cincinnati Reds had drafted him out of high school in 2015, while the New York Yankees selected him two years later. Thompson turned down both opportunities, before eventually signing with Chicago.
His early Cubs career contained plenty of promise. After a brief introduction with the Eugene Emeralds at Short A, Thompson produced a 3.06 ERA in 21 starts for the South Bend Cubs in 2019 in his first full season, still at the A-ball level. Baseball America subsequently ranked him as the ninth-best prospect in Chicago’s farm system, noting a fastball that could reach 96mph and a high-spin curveball that projected as a plus pitch.
Injuries and world events unfortunately then cost Thompson considerable development time. The cancelled 2020 minor-league season was followed by Thompson missing all of 2021 with shoulder trouble, meaning he went more than two years without appearing in a competitive professional game. He finally returned with Double-A Tennessee in 2022, but did not excel, posting a 4.42 ERA with 64 strikeouts in 57 innings.
Triple-A proved more difficult. Thompson reached Iowa in 2023 but finished 3-8 with a 5.64 ERA and 1.61 WHIP, remained there for most of 2024, and struggled again, recording a 5.95 ERA over 107.1 innings while allowing 124 hits and 48 walks. Although the Cubs invited him to major-league spring training that year, Thompson never received a regular-season call-up. He elected free agency in November 2024, ending six years in the organization without making his MLB debut.
The Bounce-Back
Moving to Korea, though, has revived his career.
Thompson signed with the NC Dinos for 2025 and became one of the league’s most productive starters in his first season. He went 17-7 with a 3.45 ERA and 1.12 WHIP over 172 innings, striking out 216 while walking 56. His 17 victories tied for the KBO lead, while he finished third in strikeouts. And as above, from there, Thompson has improved further.
Thompson’s ERA has fallen by more than half a run this season, while his strikeout rate has increased substantially. He has also cut his rate of walks, issuing only 27 in 101.2 innings after giving up 48 in 107.1 innings during his final Triple-A season. He now has 348 strikeouts in 273.2 career KBO innings, alongside a 23-8 record, 3.26 ERA and 1.09 WHIP. The stuff seems to be playing much better in the far east than it did in Iowa.
In 188.2 Triple-A innings across 2023 and 2024, Thompson had an ERA above 5.00 in both seasons and never received a major-league opportunity. The MLB was only one stop away, but the bus was not coming. In Korea, though, he has gone from struggling Triple-A starter to one of the most difficult pitchers in the league to hit. Whether Thompson’s success eventually produces another opportunity in North America remains to be seen, if he even wants it to. For now, however, a former Cubs prospect who never threw a major-league pitch has found somewhere else to become one of the best pitchers in the country.
Former Cubs Prospect Becomes One of the Best Players in Korea