FLOWERY BRANCH — Outside linebacker Sean Weatherspoon, one of the leaders of the Atlanta Falcons’ defense, will miss Sunday night’s game against the Dallas Cowboys with a right ankle injury. Weatherspoon, second on the team in tackles and sacks, injured the ankle in Sunday’s 30-17 win at Philadelphia. Coach Mike Smith said after Thursday’s practice Weatherspoon and receiver Kevin Cone, who has a groin injury, will miss the game.