The Eagles on Thursday signed punter Dirk Johnson to a six-year contract extension. Financial terms were not disclosed. The extension runs through the 2011 season for Johnson, who has been Philadelphia's primary punter for the last three seasons. Johnson missed the second half of last season due to a groin strain. Before the injury, he was 11th in the NFL with a net average of 38.4 yards, the highest by an Eagles punter since 1976. "Dirk has developed into one of the top punters in the NFL in the three years he's been with us," Eagles coach Andy Reid said.