KISSIMMEE, Fla. — After four crisscrossed years floating around the minor leagues, Josh Fields is on a mission. It’s partly religious and fully inspired. Preaching tunnel vision and tuning out a baseball world that saw him fall from the hot-armed No. 20 overall pick of the 2008 draft to a Class AA castoff, Fields has endured blocked paths with two pro teams to finally discover an opening with the rebuilding Astros. Fields (6-0, 185 pounds) entered spring training as a strong contender for a late-inning role. The righthander’s fastball approaches 95 mph, his off-speed material is strong and he’s finally harnessed control issues that derailed his early career. After two [...]