Todd Zolecki reports that the Phillies will offer Jayson Werth salary arbitration. All this means is that if Werth accepts (which he probably won't), he will be guaranteed a one-year contract with the Phillies, either at his asking price or the Phillies' offer, which would be decided by an arbiter.
Should he decline and go elsewhere (likely), the Phillies will receive two first or second round picks from the team that signs Werth. It's a win-win for the Phils. They most likely wind up with draft picks, but if Werth does accept, they have him for just one season at an undetermined price.