That's regarding an agreement about the new posting system between MLB and NPB, not whether or not Rakuten will actually post Tanaka. The basic framework of the new posting system has been in place since September; MLB / NPB have simply been working out some of the fine details over the past few weeks. Whether or not a new posting system is ratified has jack-all to do with whether or not Tanaka will be posted, which is going to boil down to Rakuten's finances given that the team just won the Japan Series and very badly does not want to let Tanaka go. But if they decide that this is the best return they'll get for him, then they'll post him.
In any event, a new agreement is an entirely different matter from the posting decision.