Sponichi mentions that around 10 teams might get involved in the Hisashi Iwakuma posting sweepstakes. That includes teams like the Diamondbacks, Mariners, Yankees, Nationals, Pirates, and Giants.
Another Sponichi article adds that Iwakuma's posting money might end up being closer to around 1.6B yen (US$20M) IF the Yankees get involved. That's double the amount that was tossed around earlier on.
Incidentally, one of the things the Yanks apparently like about Iwakuma is his tempo while pitching. It seems they have Iwakuma at about the same level as Yu Darvish.
As for Iwakuma himself, his off-season training at Kleenex Stadium currently includes weights and various stretch exercises.
Said Iwakuma, "I want to fully recovery from the season and get my body back to being 100%. I probably won't start throwing until sometime in December. I'm not too concerned about the differences in baseball."