Much credit has to go to the bullpen for pitching so well this year, even without having their closer for a chunk of it. Going into Saturday the team has a 3.23 bullpen ERA which is fourth-best in baseball. Five relievers who have played in 35+ games have sub-three ERAs which has greatly helped.
One topic of conversation regarding the pen that seems to come up is how most of the production in the pen has come from right-handers. With Mike Montgomery going to the rotation in May, there have not been a lot of lefty options in the pen.