This is obviously not good news and comes at a time when Kang appeared increasingly unlikely to face charges from the alleged sexual assault incident in Chicago due to the inability of the police to locate the accuser. It also, of course, comes in the middle of intensifying rumors that Andrew McCutchen might be traded. Kang led the Pirates in slugging last year, just ahead of Sean Rodriguez, who's now gone. He also was a close second in OPS+ to Matt Joyce, who's also gone. That was all in spite of a severe slump in the wake of the assault allegations.
Charges like DUI and leaving the scene, with no injury involved, typically would not carry the possibility of jail time in the US, but I have no idea about Korea. Of course, there's also the possibility of disciplinary action by MLB or the Pirates. With McCutchen potentially gone, the loss of Kang in the early season would be very poor timing. At least the team's debatable decision to extend David Freese is looking better now.