The fourth in a series by SportsDay's Gerry Fraley on the top prospects at each position in the Texas Rangers' minor-league system. Players on the major-league roster are not included.SHORTSTOPMICHAEL DE LEONAGE: 20HOW ACQUIRED: Signed as an international free agent from the Dominican Republic. Received $550,000 signing bonus.NEXT STOP: The Rangers have to decide if De Leon's offense would be helped by another season in the Double-A Texas League.