According to a report by Sanspo, the Yomiuri Giants and Hanshin Tigers have agreed to start the 2014 season in the US. The two teams will reportedly fly out to the US in mid-March, workout in Arizona for about a week and play a few exhibition games against MLB teams before moving on to California to play one game at Dodger Stadium and one game at Angel Stadium of Anaheim.
An official announcement will most likely be made sometime in or after May.
Source: Sanspo 4/16/2013
UPDATE 4/17 @ 3:23pm - Yomiuri Giants' team president spoke to reporters on Tuesday and said that they were still in the middle of considering their options and that they had to continue working out details with the Hanshin Tigers. The basic frame for the 2014 schedule is determined just before the summer, so the two teams will most likely make some sort of decision before then.