From Philadelphia to Buffalo and potentially back again: Defensive tackle Darwin Walker is prepared for anything, even becoming a free agent in August, after contract talks with the Bills reached an impasse Wednesday. "Whether we're done talking, I don't want to go that far," Walker's agent, Albert Irby, told The AP after talks broke down. "I've got to hope they change their mind, because I can tell you we're not changing ours." And that could mean Walker's tenure with the Bills might be a short one in what is quickly becoming one of the team's most convoluted and unusual acquisitions. Walker was acquired by the Bills in March as part of a trade that sent Takeo Spikes to Philadelphia.