The Astros are young, the organization is rebuilding and little is expected of an American League West-bound club that’s combined for 213 losses the last two seasons. In short, Houston needs a leader. Jed Lowrie’s open to the role. The sixth-year shortstop must stay healthy in 2013 to truly contribute to the Astros. Lowrie, 28,_ hasn’t played in more than 97 games during a season since debuting for Boston in 2008. But his 16 home runs and 42 RBI in just 387 at-bats last year highlighted his potential, and Lowrie will enter spring training in Kissimmee, Fla., as one of Houston’s most experienced and proven athletes. Astros manager Bo Porter [.]