According to Andrew Gross via Twitter, restricted free agents Brandon Dubinsky, Ryan Callahan, Michael Sauer and Brian Boyle will all be filing for salary arbitration today. Remember, this is not a negative thing, just "part of the process" as Dubi's agent put it. Do not be alarmed, I have full confidence that the team will get all four players signed.
Also, the arbitration filings take away the possibility of an outside team presenting an offer sheet to any of the four players. And again, this is nothing to worry about - there is a good chance most of the players will sign before their actual hearing.