Cubs rotation has been steady, but is it starting to wobble?

Despite losing Justin Steele to Tommy John surgery in April and Shota Imanaga to a hamstring strain in early May, the Cubs starting pitching staff has held it together respectably. Going into the weekend series against the Reds, the Cubs’ starters had a collective 3.95 ERA and a 3.3 fWAR. Both stats put them around the middle of the pack compared to the rest of the rotations in baseball, but the starting pitching performance through the first two months of the season has been good enough to compliment a top-of-the-league offense on the way to a National League Central division lead headed into the final days of May.

But that sturdy starting pitching performance might be starting to wobble.

In Friday’s 6-2 loss to the Reds, Colin Rea gave up three home runs in a laborious 5 2/3 inning outing. He allowed 10 hits in all and only got through one inning (the second) without putting at least one runner on base. The three homers scored all six runs, and facing Reds starter Andrew Abbott, the Cubs offense didn’t score until the Cincinnati bullpen entered the game in the eighth inning.

“The biggest thing was my misses were kind of middle [of the zone],” Rea said. “If you go back and look at the homers, they’re all kind of middle of the plate.”

Rea has been one of the steadying forces in the rotation, but Friday was his second challenging start in a row — the other, notably, was also against the Reds — and the third he has had this month. Rea gave up five runs in five innings against the Giants on May 6. And he is not the only starting pitcher who is in a rough patch. Ben Brown has also gotten touched up his last two starts, and when the Cubs’ pitching probables were announced for this weekend, Brown’s spot on Saturday was listed as TBD instead.

Manager Craig Counsell said the plan is to use an opener and then use Brown for as long as possible on Saturday. It’s a move to help Brown get past some first inning struggles that have begun to plague him this season. Drew Pomeranz was announced as the Saturday starter after Friday’s loss, and although it was not specified, the most likely scenario is that he pitches one inning and then turns things over to Brown so he can work around the first inning and start to put those woes behind him.

“The hardest innings for a starter are going to be the first inning and the sixth or the seventh,” Counsell said. “The first inning, really because you haven’t been on the mound in competition for five days. You’re facing probably the top hitters in their lineup, and it requires you to lock in immediately against the other team’s best hitters.”

Brown said that his first inning issues have been both physical and mental, but mostly the latter. He gets fired up to compete before starts; Brown told CHGO he used to get so excited before games as a kid that he’d often throw up thanks to the pregame adrenaline. So if anything, needs to be able to step back a little in order to make sure he pitches his best in the first inning.

“Then when I finally get comfortable and something goes my way, then you start seeing my stuff start to play,” Brown said. “I really think it’s just adjusting to that. That’s something we’ve addressed.”

Brown said he and the Cubs’ pitching coaches have worked on tweaking his pregame routine in order to help on this front. Avoiding the first inning on Saturday might help in the short term, but time will tell if the adjustments he is making will make a difference in future starts. Counsell is very clear that, for now, Brown is still a part of the rotation.

But until Imanaga returns, the Cubs will have to keep working toward better outings from guys like Rea and Brown. The latest on Imanaga is encouraging; he threw a 25-pitch bullpen session and went through fielding and running drills on Wednesday and will repeat a similar workout this weekend. Earlier this month, Counsell said he didn’t expect Imanaga back in the rotation until “deep into June,” and although his progress this week is positive, that timetable still holds.

All of this means the Cubs are going to have to pursue pitching depth at the July trade deadline. The front office added several pitchers during the offseason, and again, those guys — like Rea and Matthew Boyd — are a big reason the Cubs’ winning season didn’t topple with the Steele and Imanaga injuries. But team president Jed Hoyer and general manager Carter Hawkins will have to do more in the coming weeks.

They have had a lot of success in finding “project” pitchers and unlocking something in them. Pomeranz, Saturday’s starter, is the most recent example, but there’s also Chris Flexen, who has thrown 13 scoreless innings across eight appearances since coming up to the major league roster at the beginning of May. The Cubs could make a big splash and trade for a top of the rotation starter, but it is also just as likely that they continue doing what has worked well for them so far.

“We’ve had some real success stories organizationally with what we’ve done with pitching this year,” Counsell said. “We’ve got a good pitching program here, and that’s just incrementally trying to make guys a little bit better. You take shots at this, right? You take just a number of shots.

“The player deserves a lot of credit, and some you just keep looking for those opportunities. That’s the bottom line, is that you never stop, never get satisfied, never stop looking for those opportunities. That’s something the organization [does] well.”