The post became vacant after the demise of speaker G. Karthikeyan on Saturday.
“The decision to field Sakthan has been taken but no decision has been taken on who should be fielded as the deputy speaker,” Thankachen told reporters after the UDF meeting at the official residence of Chief Minister Oommen Chandy.
Sakthan, 63, is a member of the powerful Nadar community, which has a sizeable population in the capital district.
Sakthan, a former minister, is also a four-time legislator from the capital district and has been the deputy to Karthikeyan since 2011.
Sakthan’s election to the post is a certainty as, in the 140-member assembly, the UDF has 74 seats while the Left opposition has 65. One seat is vacant following Karthikeyan’s death.