According to report posted by Sports Hochi, Wladimir Balentien will most likely return to the Yakult Swallows in 2018 with a one-year deal in the three million US dollar range. The two sides are said to be in the in final stages of negotiations. An announcement could be made soon.
Source: Sports Hochi 11/21/2017
[UPDATE 11/22 @ 2:58pm]
The Swallows would like to make an announcement before the end of the month, ahead of the deadline for teams to file their list of reserved players.