This is what I found out about this ..
The link is below and for those who just wanna know the story it is copied and pasted directly from that site ..
http://www.examiner.com/x-24504-Norfolk-Comic-Books-Examiner~y2009m11d2-Adrian-Pasdar-Nathan-Petrelli-fired-from-NBCs-Heroes
Adrian Pasdar (Nathan Petrelli) fired from NBC's 'Heroes'
November 2, 8:07 PM
Norfolk Comic Books Examiner Donald Driscoll
Adrian Pasdar/Nathan Petrelli has been fired from NBC's Heroes
Blame it on the writer's strike. Blame it on the producers. But, no matter whose fault it is, fans will agree that Heroes has never quite regained that first season magic. The ratings have been falling like a flightless Peter Petrelli jumping off of that roof in the pilot episode.
Rising production costs have already seen NBC make several changes to the show.
According to Nikki Finke at
Deadline.com, the latest casualty is actor Adrian Pasdar who has portrayed lead character Nathan Petrelli since the very first episode.
Now, without spoiling too much for anyone who hasn't been keeping up with the show, given last season's finale, if anyone was on the chopping block, it'd be Pasdar's character. But, given the start of this season, it still seems like a bit of a shock. There still seemed to be plenty of story left for "Nathan."
Time will tell if this decision was a creative or business one.
Questions? Comments? Death Threats? Leave them in the Comments Section below.