How to use tablesorter to sort countdown values

How to use tablesorter to sort countdown values

Hello,
I am using tablesorter at many places in my project. Now I am in a problem.
I am using jQuery countdown to display countdown.
Tablesorter is not working on the countdown, I googled but found nothing useful.
I tried to write custom parser, but no luck, it was not working.

Please help.

Thanks in advance