ハワイ・ウィンターリーグ
Jansen split 2007 between the Raptors and the Class-A Great Lakes Loons of the Midwest League, hitting .207 in 73 games. After the season, he again played in Hawaii Winter Baseball, this time for the West Oahu CaneFires In 2008 with the Loons, he hit .227 and 9 home runs in 79 games. He was selected to the mid-season Midwest League All-Star game.