ATLANTA — The Atlanta Braves dealt outfielder Jason Heyward and reliever Jordan Walden to the St. Louis Cardinals on Monday for pitcher Shelby Miller and a minor-leaguer. The deal ends Heyward's tenure with his hometown team and lands a young pitcher to bolster Atlanta's rotation. John Hart, the Braves' new general manager, signaled the start of a major overhaul after the team slumped to its first losing season since 2008.