Dr Kumar had, during the 2006-11 period, represented Vasudevanallur assembly seat.
According to a release from the MDMK headquarters, eight people had applied to contest the by-poll election.
The former ally of AIADMK sounded confident of its victory in the Sankarankoil bypoll, adding that the result may however be immaterial. The is the first election that the party will face after it barred the April 2011 assembly polls following a break down with its former ally.
Meanwhile, AIADMK and DMK have already announced their candidates for the by polls.