mlbtr says the Mariners are going after Fielder, if there's a team that is the perfect fit for him, it's seattle. They desperately need hitting, they can move him into the DH role eventually, and they have plenty of good seafood restaurants (assuming he eats fish).
BP says his hitting will play neutral in Nats Park, negative in Seattle (would have lost about 5 HR this season). This was in the context of value as a fantasy player.