According to Daily Sports, the Marines are currently looking into Tsuyoshi Shimoyanagi (43). An Ikusei deal is a possibility.
Lotte apparently likes Shimoyanagi because he is an experienced left-handed veteran that is capable of starting. While the team does have other left-handed options, like newly drafted players Takahiro Fujioka and Yuhei Nakaushiro, there is concern about whether or not they will be ready and Shimoyanagi could be used as a temporary stopgap until they are.
Daily Sports also notes that the Marines currently have 65 players on their 70-man roster and may look to sign two foreign players and Saburo.