The Cubs opened the season with an eight-man bullpen, but they've essentially gotten the benefit of having 12 relievers this season.
Much of the good work has been done by such unheralded pitchers as Randy Rosario, Luke Farrell, Cory Mazzoni and Justin Hancock, who is now back at Class AAA Iowa.
Injuries have played a part in a bullpen that has been effective, even with a revolving door.
Lefty Mike Montgomery moved from the bullpen to the starting rotation when Yu Darvish went on the disabled list for the second time this season.
Relievers Carl Edwards Jr. and Eddie Butler currently are on the DL. Rosario has an ERA of 0.84 while Mazzoni is at 0.00. Farrell sucked up 5 innings of relief work June 2 in a 14-inning victory at New York.
"Even some of the guys who have been sent back (to the minor leagues)," manager Joe Maddon said Saturday. "Hancock has done a great job also. I think it speaks to the off-season again. It's your off-season that permits this kind of stuff to happen. I think the (front office) guys did a really good job of identifying and then signing guys they thought could help us this year. Wonderful job. We talked about it in camp. I remember talking about Rosario specifically. Really thought he was interesting.
"Mazzoni, you watch him and you start to acquire a taste there because his slider is so good, and there's more velocity than you think. Hancock, what a great arm. We've talked about him, also. They've all been contributing. There's this ability to move guys around."
Yu Darvish played catch on the outfield grass Saturday morning as he continues his slow recovery from right-triceps tendinitis.
Darvish lengthened out his throws, but he is not yet ready to throw off a mound, according to Joe Maddon, who added Darvish would need a minor-league rehab stint once he's ready to pitch.
"I talked to him (Friday)," Maddon said. "The pain is subsiding. It's becoming more like the soreness we had talked about so it's a good thing. But he's still not ready to get to the mound yet. He's still just in a play-catch mode.
"Everything is advancing, not quickly, but it's advancing. I think by the end of next week, we should have a pretty good idea where we're at."
Carl Edwards Jr., who is on the DL with right-shoulder inflammation, continues his strengthening program but has not played catch yet, according to the Cubs.
"He's doing really good," Joe Maddon said. "I don't know exactly where we're at in the throwing part of it, but strength level has really come back up.
"Things are trending well. I don't have any kind of conclusions yet, but strength level is up, getting where it needs to be. I think he's not really feeling what he had before so it's a good sign. He's smiling a lot, which I like."