At some point, likely in July, the Cubs are going to get Yu Darvish back from a triceps injury. When they do, assuming no other injuries in the meantime, they will have six quality rotation options. Consider: 

  • Jon Lester and Kyle Hendricks obviously aren't going anywhere. Jose Quintana isn't either, and he's put his early struggles behind him with a 2.65 ERA in his past six starts. 
  • Yu Darvish's career track record suggests that once he returns in good health, he'll be a frontline starter. 
  • Tyler Chatwood is walking batters at a historic pace. He also has a 3.95 ERA, which is perfectly fine for a number five starter. It's not like one could justify moving him to the bullpen with that walk rate. Plus, if his walks normalize to his career norm (roughly 4.5 BB/9, compared to 8.43 this season), he'll be a good fifth option. 

That's five. And then there's Mike Montgomery. Heading into his Tuesday night start, Montgomery has a 1.14 ERA and 0.69 WHIP in his four starts since joining the rotation. We can obviously expect some regression at some point, but he's more than getting the job done in the role he's been given. Should they keep him in there? 

Recently, general manager Jed Hoyer commented on the matter, via suntimes.com: 

"We'll use common sense," Hoyer said. "This guy's pitching so incredibly well. All he's done is taken that opportunity and done all you can with it. We're obviously going to keep that in mind.

"I'd be careful not to take what I said and turn it into someone losing a rotation spot, either," the GM added. "We have the ability to do many different things. But I would say we've noticed what Mike's done."

Leaving Montgomery in and making it a six-man rotation might be the way to go here for Joe Maddon. 

First, the group here has the ability to be one of the best rotations in baseball. Secondly, the Cubs are planning on another deep postseason run, which means conserving the bullets of the rotation is a priority. Having everyone pitch essentially once a week buys a few starts off for everyone the rest of the way. 

What's more, the pitchers in the rotation -- in getting extra rest between starts -- could go deeper into games and that allows the Cubs to rest the bullpen. 

It's a trickle-down effect that would really help. As things stand, the Cubs haven't really overworked their bullpen, but guys like Steve Cishek, Pedro Strop and Carl Edwards Jr. (pre-injury) have been used an awful lot. They need to continue be careful with closer Brandon Morrow, too, given his injury history. 

It's all part of the equation. Keep Montgomery in the rotation, get the rest of the starters extra rest, work them deeper into games and preserve what's been an excellent bullpen. Entering Tuesday, only the Astros had a better team ERA than the Cubs in all of baseball. Getting a healthy Darvish back and leaving Montgomery as a starter would only make the situation better.