Randy Messenger is slated to earn his domestic free agent option on April 16 (assuming he remains on the active roster until then). According to reports by Daily Sports and Sanspo, the Hanshin Tigers are planning to ask him to stay as soon as he earns the option. Messenger has also expressed an interest to remain with the team.
While it is still early, there is a good chance the Tigers will offer a multi-year deal with at least two years. If Messenger becomes a free agent, he will be an interesting option for other NPB teams because he will no longer be considered a foreign player.
[UPDATE 4/14 @ 1:49am]
According to a report by Tokyo Sports, Messenger is willing to play for as long as the Tigers want him (if they want him for two years, he will play another two years). He is also not interested in playing for any other team in Japan.
Source: Tokyo Sports 4/13/2018