With the main opposition YSR Congress (YSRC) deciding to stay away from the process, TDP leaders said election of Prabhakar is expected to be a certainty.
Filing of nominations for the MLC election ends tomorrow while polling, if required, will be held on January 12.
The by-election for the Kurnool LAC seat was necessitated after incumbent Silpa Chakrapani Reddy resigned from his post in August, just three months after his election as TDP candidate. Reddy then joined the YSRC.
Prabhakar is the younger brother of Deputy Chief Minister (Revenue) K E Krishna Murthy.
He has previously served as a minister in the Chandrababu government in erstwhile united AP.
Prabhakar was in June this year appointed as Chairman of AP State Irrigation Development Corporation.