First fan post and I will make this short.
Tanaka is all the rage in Japan. He is coming off a championship and is extremely popular among the Japanese. One thing that we cannot forget is that with the Mariners new regional sports network is that they also gain royalties for games aired internationally. While I don't think we can expect every Mariners game to be broadcast nationally in Japan, we can likely expect a few million dollars in selling games' broadcasts to international programmers. We can also likely expect merchandise sales both internationally and domestic. We even have a case example in Ichiro with the kind of fervor that can follow a Japanese superstar that succeeds stateside. While this is somewhat contingent on success, I feel fairly confident that Tanaka can be a star and is a potential superstar. Let's say conservatively, the international broadcasting and merchandising adds up to between 5-7 million dollars in the first year. It's enough to defray the upfront posting costs enough to make a deal more likely.
Historically, we have seen the Mariner's business side get in the way of the baseball product that is sent onto the field. This seems like a perfect opportunity for the business people and the baseball people to find a way to make the Mariners much more profitable and successful.