Somebody had to pitch at the front end of the 2015 Reds bullpen, and that person turned out to be Ryan Mattheus in large part. He didn't make much of a case for a promotion to working the later innings, but he didn't single-handedly lose a bunch of games or have terrible results, either. The Reds project to have a bunch of inexperienced starters in the rotation again next year, and in such cases you are going to need guys in the bullpen who can chip in a lot of not-terrible low-leverage innings and keep the team in the game.