MILWAUKEE — Everything had set up for Cubs manager David Ross to run out his bullpen arms in the way it had worked best over the last month.

Drew Smyly only lasted 3 2/3 innings before Ross brought in Michael Fulmer to try to clean up a two-out, runners at second and third situation in the fourth. The veteran Fulmer began the season as one of those backend relievers, but he was inconsistent in high-leverage spots early on and had since moved into more of a middle-relief role.

Still, he’d found a lot of success in that position. Through May 27, Fulmer had owned a 7.84 ERA. But the 14 games after that, he posted a 0.60 ERA with just one earned allowed in 15 innings. With Ross hoping to get to a lineup of Julian Merryweather/Mark Leiter Jr./Adbert Alzolay to close out the game with what was then a three-run lead, he tasked Fulmer with getting the Cubs through the middle innings — and Fulmer delivered.

He covered 2 1/3 innings to get the Cubs to the bottom of the seventh — the spot in which Ross wanted to use Merryweather — with the three-run lead intact. It even got to the point that Fulmer, after the Cubs burned the designated hitter by moving Christopher Morel from DH to third base in place of an injured Nick Madrigal (who left the game in the bottom of the fourth with right hamstring tightness), took his first at-bat in exactly five years in the fifth.

With Fulmer locking down the middle innings, that set up the ideal scenario for Ross’ late-inning bullpen usage:

• Merryweather had turned into a pretty reliable option. He allowed eight earned runs in his first five appearances, but over his next 30 heading into Monday, Merryweather had recorded a 0.93 ERA and hadn’t given up a run since May 26
• Leiter owned a 2.41 ERA on the season, and he’s been the Cubs’ best arms against left-handed hitters (though he’s been effective against righties in 2023, too)
• Ross still hasn’t technically named anyone the closer, but Alzolay has emerged as arguably Ross’ best ninth-inning option and had recored a 2.05 ERA through the first half of the year

As expected, Ross brought in Merryweather to face the top of the order in the seventh with an eye on handing the ball off to Leiter and Alzolay in the final two innings. But it never got to that point.

Milwaukee put together a long, two-out rally against Merryweather, who issued back-to-back free passes to load the bases. A bit of gamesmanship led to Anthony Kay facing off against recently signed Brewers pinch hitter Jahmai Jones (who had just joined the team Monday), and on Kay’s first pitch, Jones smoked a double over Cody Bellinger’s head in center field to clear the bases. Leiter did put out a fire to end a second bases-loaded threat in the frame, but Milwaukee scored twice off him in the eighth to complete the comeback in the 8-6 Cubs loss.

“Fulmer was great. Huge 2 1/3 to set us up to be Merryweather, Leiter and Adbert,” Ross said. “We just couldn’t close it out.”

The bullpen had drawn the ire of the fan base for much of the first two months of the year, but after the calendar flipped to June, the group found a groove. Entering Monday, the Cubs’ 2.50 bullpen ERA since June 1 was the second-lowest in baseball. That success played a big part in the team’s 11-2 record in the 13 games after getting swept in Anaheim almost a month ago. Which is what made the meltdown that cost the Cubs an important division game all the more frustrating.

“The bullpen has been great,” Fulmer said. “The guys down there have been throwing the ball really well the whole month of June. We had our talks before June and telling ourselves that we needed to pick it up. I think today is just kind of a blip in the road. I mean, everybody kind of had trouble throwing strikes. Those days are going to happen, but we’re a lot better than what we were today and going to need to figure it out for [Tuesday].”

The relievers aren’t totally to blame for the loss. Again, Smyly’s short outing forced them to cover what would’ve been 5 1/3 innings had they held onto the lead. And the offense, even with the bottom five spots in the lineup giving them six runs worth of production, couldn’t get anything going after the third inning.

That’s just been the story of the last week-plus for the Cubs. From gut-wrenching losses (like Sunday, when they forced extras with a four-run ninth-inning rally just to take the loss anyway) to lackluster performances (one or zero runs scored in three of their seven losses since last Sunday), they’ve hit a rut that has nearly erased all the good they did in the two weeks prior. They got as close as one game below .500 after the London Series-opening win, but they now sit seven games under and seven games back in the National League Central.

In their final 13-game stretch leading into All-Star-break, the Cubs have lost six of their first seven contests. Time is running out for the team, as least when it comes to the trade deadline.

The Cubs will continue to say they need to take things one game at a time, but when the number of games continues to dwindle, so does the margin for error. And with just six games left before the break, it feels like this could be their last opportunity to save their season.

“I hate to say it, but I think they’re must-win games,” Fulmer said of the remaining games against the Brewers and Yankees. “We’re better than what we’ve been playing right now, everybody in every aspect. When we have a lead like that, we’re going to need to be able to hold it. So, no matter who it is or what day or how you’ve been pitching, we’ve got to figure out a way to get it done.”