CHICAGO — It wasn’t until a month into the 2025 season that Chris Flexen first took the mound for the Chicago Cubs.

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Looking back, it’s something that seems incredulous given the way he’s pitched. The 30-year-old right-hander is now riding a 21.1-inning scoreless streak, complete with 13 strikeouts and a 0.84 WHIP in his 12 appearances thus far.

When the Cubs hosted the Brewers on Thursday, Flexen kept his 0.00 ERA — even when he took over against a Milwaukee offense that jumped on starter Jameson Taillon for five runs on eight hits over four innings.

“I put us in a hole there,” Taillon said after the Cubs’ 8-7 loss. “Testament to the guys on offense and the bullpen just to keep us in there. Flex, especially — he’s been incredible.”

The Cubs trailed 8-3 when Flexen entered the game. They desperately needed somebody to come in and calm the storm that was brewing, and Flexen did just that. He struck out three over three innings, and on the other side, the Cubs’ offense came clawing back.

“It’s a cool feeling as a pitcher, just to know you can have a bad day and still, your team can fight and be in it,” Taillon said of Flexen and his teammates’ collective effort to make the game close.

Flexen signed a minor league deal with the Cubs in the offseason and spent April with Triple-A Iowa. His three-inning, four-strikeout introduction for the Cubs on May 2 was one that cemented him as a force to be reckoned with in a bullpen that had been struggling.

Right before Flexen joined the team, the Cubs’ bullpen was sporting a 4.64 ERA — eighth worst in MLB. Now with Flexen’s help, they’ve made incredible strides — so much so that their 1.99 ERA since May 2 is the best in MLB. They’ve also lowered that season ERA to 3.15 and have skyrocketed to fourth-best in the league overall.

“He’s pitching really, really well,” Cubs manager Craig Counsell said of Flexen after the game Thursday. “(We) kind of anticipated him pitching in those in the longer situations more, and he hasn’t done that in a while.”

Flexen has formed a tandem with another mid-season addition in Drew Pomeranz, who has a scoreless streak of his own that stands at 19.1 innings.

“I feel like we both have just kind of been going out there and pounding the zone,” Pomeranz said. “The whole bullpen’s done a really good job … Just coming in and attacking guys, trying not to give up free bases and just getting in and getting out real quick.”

The postponement of Wednesday’s game certainly threw many teams’ pitching plans for a loop. When Taillon couldn’t provide the length that the Cubs perhaps needed heading into a tough weekend series against the Seattle Mariners, Flexen jumped in and saved some arms that Counsell was happy he didn’t need to use.

“To come out and be able to give us three innings, it’s going to help us this weekend, absolutely,” Counsell said. “It was an excellent job by Chris.”