In his first professional season, Mottola led the Billings Mustangs to the Pioneer League championship, batting .286 with 12 home runs and 37 runs batted in (RBIs). Baseball America rated Mottola as the 71st best prospect in baseball before the 1993 season. Playing a full season for the first time in 1993, he batted .280 for the Winston-Salem Spirits with 21 home runs and led the Class-A Advanced Carolina League with 91 RBIs. He was named a Carolina League All-Star outfielder after the 1993 season. Prior to the 1994 season, Baseball America rated Mottola as the 43rd best prospect in baseball.
