NHL News: Nikolai Zherdev returns from the KHL to sign with the Flyers RW Nikolai Zherdev signs with the Philadelphia Flyers (1 years, 2M) D Niklas Hjalmarsson signs an offer sheet with the San Jose Sharks (4 years, 14M) The Chicago Blackhawks have 7 days to match the offer, if they don’t they will receive…