According to ELIAS

No adjustment period for Zimmermann

Bill McAfee
Bill McAfee

Jerry KoosmanJordan Zimmermann allowed one run in seven innings at Minnesota yesterday to improve to 5-0 on the season. Zimmermann, who signed with the Tigers this past offseason after seven seasons with the Nationals, is the fourth hurler ever to earn a victory in each of his first five games in the American League after having previously pitched in the National League. Bill McAfee was the winner in each of his first five appearances (two starts, three in relief) for the Washington Senators in 1932. Jerry Koosman won his first five games, all starts, for the Twins in 1979 after having a 3-15 record for the Mets the previous year. And Matt Palmer earned the victory in his first five appearances, all starts, for the Angels in 2009. Zimmermann’s 0.55 ERA is far lower than that of McAfee (2.49), Koosman (3.86), and Palmer (4.26) during their 5-0 starts.