This was reported by a Japanese baseball site a few weeks back, but it appeared nothing was going to come of it. But now Scott McCauley has tweeted that it is done. I'm not sure what brought this about or whether it was Penn's desire to move to Japan.
What is very interesting is that McCauley is also reporting that another Indianapolis pitcher may be close to a similar deal. Maybe the Pirates gave a few guys an opportunity to explore their options since they will have so many pitchers coming up through the organization. But, Penn seemed like he still had a chance to be useful.
UPDATE: Vinnie Chulk is the other Indianapolis pitcher about to make this move, according to DK.