Magadan was listed at , , batted from the left side, and threw from the right. While a 17-year-old senior at Jesuit High School of Tampa, Magadan was selected by the Boston Red Sox in the twelfth round of the 1980 Major League Baseball draft, but elected not to sign. His status as a prospect improved after he led West Tampa Memorial Post No. 248 to a win against a team from Richmond, Virginia in the American Legion World Series and was named series Most Valuable Player. He also received the George W. Rulon American Legion Baseball Player of the Year award.