Jung-Ho Kang will leave for Pittsburgh Wednesday morning, his Korean team, the Nexen Heroes, has announced. (I don't read Korean, obviously, so I'm trusting Google Translate, Dan at @MyKBO and Jeeho Yoo here.) Kang will then take his physical with the Pirates on Thursday and Friday. The Heroes have even included Kang's flight number, if you're feeling creepy.
If all that is correct, it sounds like the Pirates and Kang probably have at least the framework of a deal in place -- I can't imagine he'd come all the way to Pittsburgh for a physical without being ready to sign. Assuming the two sides do reach a deal, Kang will remain in the US. The Pirates' exclusive negotiating window with Kang closes early next week.
Jon Heyman had previously reported that the Pirates were close to agreeing with Kang on a deal that would likely be for four years. Jon Morosi then tweeted that Kang's deal would likely be done by the middle of this week. It might take a day or two longer than that, but based on Kang's travel schedule, you can see how Morosi might have gotten that impression.