Rangers minor leaguer Leodys Taveras, an 18-year-old center fielder, established himself as a high-level talent in his first professional season.Baseball America named Taveras as the top prospect in the short-season Class A Northwest and the rookie level Arizona leagues. The ranking was based on a survey of managers, coaches and scouts.Yoan Moncada, a 21-year-old third baseman in the Boston organization, is the only other player to be designated as the top prospect in two leagues this season.