Stammen is middle relief. Gorzo can handle long relief if they need to
Rather not have two guys that are left handed be the long relievers. Yes Gorzo can do it, but Stammen isn't a one inning wonder (most I would use him is two though, same with Gorz)
Also I wouldn't leave Burnett off if he just isn't pitching well. I still think he is hurt. I would only leave him off if he is hurt, and he shouldn't "play through it" because it is costing the team.