As per TSN:

The Tampa Bay Lightning are expected to announce a multi-year contract extension for defenceman Victor Hedman on Wednesday.

There is speculation the deal could be about five years in length with an annual salary cap hit in the neighbourhood of $4 million per season.

This season, Hedman has two goals in 20 games with a rating of minus-5.

Hedman was drafted second overall in the 2009 Entry Draft and was slated to become a restricted free agent at season's end.

I'll update later when I hear more solid info.