Time for a new challenge — already — for Ronald Acuna, one of the top prospects in Atlanta’s loaded minor league system. The 19-year-old Venezuelan is expected to debut for the Double-A Mississippi Braves tonight at Trustmark Park. A 6-foot, 180-pound center fielder, Acuna was batting .287 with three homers, 19 RBIs, five triples and 14 steals through 28 games at high Class A Florida. He played at low A Rome in 2016, batting .311 with four homers and 14 steals in 40 games. He is a consensus top 10 prospect in Atlanta’s system and is rated No. 92 overall by MLB Pipeline. Acuna’s “ceiling is as high as anyone’s in the (Braves) system,” MLB Pipeline writes.