The Mariners’ first free-agent signing of the offseason was indeed a pitcher. But it wasn’t from the typical talent pool that most expected.

An MLB source confirmed that right-handed pitcher Chris Flexen has agreed to a two-year, $4.75 million major-league contract with the Mariners. The club has yet to announce the deal as the result of Flexen’s physical is pending.

If you haven’t heard of Flexen, you probably weren’t watching this year’s TV broadcasts of the Korean Baseball Organization games in the wee hours of the morning. Pitching in parts of three seasons in Major League Baseball with the Mets and producing three less-than-remarkable performances, Flexen found success pitching for the Doosan Bears of the KBO.

In 21 starts Flexen, 26, posted an 8-4 record with a 3.01 ERA. In 116 2/3 innings, he struck out 132 with 20 walks.

It’s unclear if the Mariners will use him as a starter, reliever or swing pitcher who can do both. They plan to use a six-man rotation in 2021.

Flexen pitched as a starter and reliever for the Mets while being plagued by command issues. He made 11 starts and 16 relief appearances, posting a 3-11 record with an 8.07 ERA. In 68 innings he struck out 49 and walked a whopping 54. He allowed 14 homers.

He was 14th-round pick in the 2012 draft out of Memorial High School in Newark, California, and made his big league debut in 2017 at age 23. He was mostly a starter at the minor-league level, posting a 43-31 record with a 3.61 ERA in 122 appearances and 588 innings.