Johnson spent ten years in the minor league organizations of the Detroit Tigers and Houston Astros.
[3] Johnson opened the 2001 season with Oneonta, where he went 7-1 in twelve starts with a 3.42 ERA before being promoted to the Single-A West Michigan Whitecaps in late August.
His highlight performance occurred on July 30, when he threw six shutout innings in a 9-1 victory over the St. Lucie Mets.
In 2007, he finally reached the Triple-A Toledo Mud Hens, going 3-3 with an ERA of 3.44 in 39 appearances; for the first time mostly in a relief role.
[7] Johnson signed with the Houston Astros AA affiliate Corpus Christi Hooks as part of the starting rotation for the 2010 season.