 He learned baseball at an early age , his biggest rival being Juan González , who he often played against in his youth . As a Little League player , he moved from pitcher to catcher because his father , who was also his coach , thought he was throwing too hard and scaring opposing players with his pitches . Rodríguez attended Lino Padron Rivera High School , where he was discovered by scout Luis Rosa . Rosa reported that " He showed leadership at 16 that I 'd seen in few kids . He knew where he was going . " Rodríguez signed a contract with the Texas Rangers in July 1988 , at the age of 16 , and began his professional baseball career . 
