The Pittsburgh Pirates reached an agreement Monday with South Korean shortstop Jung-Ho Kang on a four-year deal worth approximately $16 million, a source told ESPN MLB Insider Jim Bowden.

Shortstop Jung-Ho Kang hit .356 with 40 homers last season for the Nexen Heroes of the Korean Baseball Organization. BAY ISMOYO/AFP/Getty Images

The deal, which is pending a physical, also has an option for a fifth year, the source said. The Pirates had a 30-day window to come to an agreement after winning negotiating rights on Dec. 22.

Kang, 27, hit .356 with 40 home runs and 117 RBIs in 501 plate appearances for the Nexen Heroes of the Korean Baseball Organization in 2014. He flew to Pittsburgh on Wednesday and is expected to take a physical on Thursday.

Since Kang reached an agreement with the Pirates, Nexen will receive the posting fee for his rights, which the Yonhap News Agency reported to be just more than $5 million.

The Pirates were searching for depth in the middle infield behind second baseman Neil Walker and shortstop Jordy Mercer.

The Associated Press contributed to this report.