pkKumar - 10:25 am on Jan 12, 2013 (gmt 0)

From your comments, it sounds like you don't have enough good links for you to be interlinking the sites as you are

It might be true, since the link is on a masterpage header, so it will repeat on every page and there are whole lot of pages on the site.
Is rel="nofollow" a good option, since i have to make changes to few pages only.
One more thing its there for more than 4 months and i have not received any warning or penalty from google. Yes i have no page rank but doing well in google search for target keywords.