The Mississippi Braves, who faltered late in their chase for a first-half championship in the Southern League, may get a lift in the second half from the addition of Robby Hefflinger, an outfielder who was putting up big numbers at Class A Lynchburg. Hefflinger, who went 0-for-4 (with a couple of hard-hit balls) in his Double-A debut at Trustmark Park on Saturday, was leading the Carolina League in home runs with 21 and slugging percentage with a .579 mark. He was batting .286 with 52 RBIs. He’s a right-handed hitter with an Evan Gattis-like build (6 feet 4, 220 pounds) and reportedly is a pretty good outfielder. Hefflinger, 23, Atlanta’s No. 29-rated prospect entering 2013, was a seventh-round pick in 2009 out of Georgia Perimeter Junior College. Atlanta released outfielder Kyle Russell, a spring free agent signee who never really provided the left-handed power the M-Braves were hoping to get from him. … Meanwhile, ex-M-Braves standout Jeff Francoeur was designated for assignment by Kansas City, which essentially means he’s done there. The one-time Sports Illustrated cover boy, who seemed to have stardom written all over him back in 2005, was batting just .208 with three homers in 59 games for the Royals. He struck out in his last at-bat for them on Saturday. There is speculation that San Francisco and the New York Yankees might have an interest in Francoeur, who is still a very good right fielder. But he might have to go back to the minor leagues.