The ESPN.com report said the Pirates reached an agreement with Kang on a four-year deal worth approximately $16 million. The report added that Kang's deal is pending a physical and has an optional fifth year.
The 27-year-old has played in the Korea Baseball Organization (KBO) for nine years.
The Nexen Heroes, Kang's KBO club, said Kang will leave for Pittsburgh, Wednesday, and will go through medical checks Thursday and Friday.
In his nine years with the Heroes, Kang recorded a batting average of .298 with 139 home runs in 3,070 at bats, establishing him as one of the best shortstop batters in the league.
His breakthrough came last year when he became the first shortstop in the KBO history to reach the 40 home run milestone. Overall, he had 149 hits, including 40 homers, 36 doubles, 117 RBIs and 103 runs in 117 games last season.
During the offseason, the Heroes posted Kang for MLB clubs, and the Pirates won the bidding for Kang with a bid of $5,002,015 last month. The Pirates acquired exclusive rights to negotiate with Kang for 30 days, which would expire on Jan. 20.
If the deal goes through, Kang will be the first Korean position player to join the MLB via posting.