The New England Patriots have begun addressing a group of 17 veterans eligible for unrestricted free agency by signing versatile linebacker Don Davis to a one-year contract extension that will keep him off the open market and quell any thoughts of retirement. A 10-year veteran, Davis might not seem like a player who would be significant for the Patriots to retain. But his ability to play all three linebacker spots, to fill in at safety when necessary, and to remain a standout special teams performer made him a priority. Davis, 33, signed a one-year contract that included a signing bonus of $25,000 and a base salary of $770,000, the league minimum for a player of his seniority. He will count only $485,000 against New England's salary cap for 2006, because of the break teams get for signing veteran players to minimum-salary deals.