 He was signed as an amateur by the Minnesota Twins in and was drafted by Boston that November.After a stellar 18–8 record and a 2.26 earned run average in the 1965 Double-A Eastern League, Magrini made his Major League debut for the Red Sox on April 13, against the Baltimore Orioles, going two innings and giving up two hits, two bases on balls and three earned runs.He made his only MLB start in his final game May 9 against the Kansas City Athletics but lasted only three innings and lost his only big-league decision, 6–1.