The team designated the South Korean third baseman/shortstop for assignment on Friday. Kang hit .169 with 10 home runs and 24 RBIs in 65 games this season.
Kang, 32, signed with Pittsburgh in January 2015, becoming the first position player to jump directly from the Korean Baseball Organization to the majors. He made a splash as a rookie, finishing third in Rookie of the Year voting after hitting 15 home runs. His season ended abruptly that September when he broke his leg after getting taken out at second base by Chris Coghlan of the Chicago Cubs.
Kang returned in 2016 and hit 21 home runs before his career went into a tailspin after getting arrested in Seoul in December 2016 on charges of driving under the influence of alcohol.
Kang received a two-year suspended sentence, spent the entire 2017 season on the restricted list after being unable to secure a visa back to the U.S. and played in just three games at the end of the 2018 season. The Pirates cut him last September before bringing him back on a one-year deal worth $3 million.
Kang played well defensively while splitting time at third base and shortstop, but he failed to find any sort of consistency at the plate. He never hit better than .222 in any month this season.
"As hard as he's tried and the work that he's put in, it hasn't transferred to the game right now," Pirates manager Clint Hurdle said. "So that's the hard part. ... We saw a guy come in here and was a significant player, a significant addition to the lineup with a power component that was real and a style of play that worked. The time away though, seemed to affect him more offensively than defensively."