Injuries aside, Chicago Cubs' bullpen just keeps doing its job

If there's one rule of thumb - or shoulder or elbow - that will serve you well when it comes to understanding the long baseball season, it's this: The bullpen a team starts the season with is never the one it finishes with.

Never.

We're seeing that play out with the Chicago Cubs, whose bullpen has been a strength of the team all season long through constant change.

The Cubs found themselves with two more changes recently when Pedro Strop went down with a hamstring injury and Brandon Morrow was shut down for the rest of the year.

Shutting Morrow down was hardly a surprising development. He had not appeared in a game since July because of a biceps ailment. Strop had been doing a fine job since he was felled by a strained hamstring last week in Washington.

Now, the Cubs regroup again, for the rest of the regular season and possibly into the postseason.

The way they have handled the bullpen all season long has been both interesting and effective. They have used 22 relievers (including current starter Mike Montgomery and erstwhile starter Tyler Chatwood), and yet they entered Wednesday night's series finale at Arizona leading the National League in bullpen ERA at 3.28.

Early this season, the Cubs got contributions from the likes of Eddie Butler (since traded in the Cole Hamels deal), Luke Farrell, Justin Hancock, Anthony Bass and Randy Rosario. Almost all of these pitchers had little meaningful big-league experience.

The Cubs made wise use of their "Iowa shuttle" with these and other relievers who had minor-league options and were pitching for the Cubs' Class AAA Iowa affiliate.

While all that was going on, manager Joe Maddon rightly pointed out that the Cubs would need veterans to step up later in the season when the games started to mean more. But let's do give a doff of the baseball cap to Rosario, who has been solid all season and who did pick up his first career save in relief of Strop last week in that key makeup game at Washington.

Strop certainly stepped up when called on to close after Morrow went on the disabled list. Steve Cishek has been a rock all year, and Justin Wilson has looked like the reliever the Cubs hoped they were getting last year when they obtained him in a trade with the Detroit Tigers.

Then the front office went out and got Jesse Chavez, Brandon Kintzler and Jorge De La Rosa, none of whom were on most Cubs fans radars at the beginning of the season.

Chavez has been the real gem here. In 27 games since his trade from Texas in mid-July, he was 2-1 with a 1.44 ERA, 3 saves and a tidy WHIP of 0.89 entering Wednesday.

Even though Maddon never "ordained" Strop as the closer - "he has not been to the Vatican, and he's not received the holy oils," the skipper said - Strop did pile up 13 saves before getting hurt while moving into 11th place all time in appearances (361) for the Cubs.

So what do Maddon and the Cubs do now with the bullpen and the closer's role? The same thing they've been doing: play the matchups and be fearless. Since Strop got hurt, the Cubs have gotten saves from Rosario, De La Rosa and Cishek.

If that kind of work keeps up, there will be no need for Maddon to summon help from the Vatican or anybody else.

• Bruce Miles will be a guest on CLTV's SportsFeed show at 6 p.m. Thursday. You can follow Bruce on Twitter @BruceMiles2112.