U.S.S. Mariner has done a depth chart for the A.L. West, setting out the lineups, rotations and pens of the 4 A.L. West teams.
As Derek points out at the end of his post, this helps illustrate the fact that this is a pretty mediocre division. You have four teams, all of whom could very well end up with between 80 and 90 wins.
Which is part of why the Rangers are pushing to add pieces for right now...this is an imminently winnable division...