This story was excerpted from John Denton’s Cardinals Beat newsletter. Jackson Stone filled in on this edition. To read the full newsletter, click here. And subscribe to get it regularly in your inbox.

KANSAS CITY -- JoJo Romero’s emergence as a reliable reliever has transformed the Cardinals’ bullpen.

It was an area the Redbirds knew they needed to target after pitching to a 4.47 ERA out of the ‘pen in 2023 -- 13th in the National League. And there were moves made to address it, trading for Andrew Kittredge and signing Keynan Middleton to go along with a bundle of acquisitions to solidify the rotation in Sonny Gray, Kyle Gibson and Lance Lynn.

But the unnoticed hero of the Cardinals’ turnaround in the reliever department? Romero.

The five-year veteran, who had a 7.89 ERA in 25 games with Philadelphia from 2020-22 before getting traded to St. Louis for Edmundo Sosa at the 2022 MLB Trade Deadline, has quickly become one of the Redbirds’ go-to arms in high-leverage situations.

When the Cardinals acquired Romero in 2022, there were signs that his forward-facing numbers were misleading. He had a 35.5% whiff rate in his final year with the Phillies, and things have changed dramatically for the better in ‘23 and ‘24.

Part of that improvement, according to Romero, is due to the aforementioned offseason additions.

“Just kind of growing and adapting. We brought in a lot of veterans around that have really helped with understanding the game from a different aspect, really being a sponge and absorbing it all,” Romero said. “Just growing mindset wise, approach wise and understanding what I need to do on a daily basis to be ready and be as effective as I can possibly be.

“We’re pretty confident down there all together. We feed off each other and we’re pulling for each other.”

So far, he couldn’t have been much better. Romero has already set career bests in innings (48) and WHIP (0.98), all while compiling a 4.8% walk rate and a 20.6% strikeout rate. He’s also stranded 17 of his 25 inherited runners and has yet to throw a wild pitch.

And that’s in addition to pitching in high-leverage situations. The lefty had 10 career holds in his first four seasons in the Majors, never topping more than four in a single campaign.

This year? Romero has 28 -- tied for the third most in the Major Leagues with the Royals’ Hunter Harvey.

“Just doing whatever is asked of us. That situation, it’s obviously the sixth, seventh, eighth inning. Whenever we are coming in, the job is to keep the game where it’s at to give us the best chance to close it out,” Romero said. “With that approach, going in there and doing whatever job is asked of us.”

That newfound trust from the Cardinals’ staff this season has also improved Romero’s confidence. The 27-year-old said he’s learned to have a short-term memory mindset to go along with his belief that he’s better than whoever steps in the box.

It’s just another quality that Romero has learned from his peers in the bullpen, and it’s a good group to learn from. Kittredge has been as effective as anyone, striking out 49 batters and picking up a save to go along with his 3.02 ERA. The righty has 30 holds -- the most in MLB -- and has eclipsed the 50-inning mark for just the second time in his career (2021).

Throw in Ryan Helsley, who leads the Majors with 37 saves, and it’s one of the most formidable back ends to a bullpen in baseball.

“We got a bunch of really good dudes down there, and I think that speaks more than the talent that we have. And we have a lot of talent down there, too,” said reliever Matthew Liberatore. “It’s just made it easy every day, whether we have a good outing or bad outing, to be the same guy every day. Nobody hangs their head. Everybody is vulnerable with each other, which I think is really important. We just have a lot of fun.”

That camaraderie has not only helped Romero, but it’s fueled big performances from different pieces in the ‘pen all season. Liberatore was the latest example, tossing three frames of hitless ball against the Royals on Friday to spark the comeback win. Ryan Fernandez, in his first season in the big leagues, has also been a welcome surprise, as has Kyle Leahy.

Part of the Cardinals’ success from the ‘pen is due to the development of young relievers. Another part is the experienced veterans coming in and doing their job. The final part is the longtime mainstays continuing to lock down games.

As long as the Redbirds continue to get this type of production from their relievers, they’ll already have one of the most important pieces for a postseason push.

“I think it’s not just one person specially or anything. I think we’ve done a really good job as a group of limiting damage. … I think we’ve understood what’s being asked of us and we’ve done a great job of going into each outing, each game and executing that to the game plan,” Romero said.

“We’ve seen that all throughout the course of the season, not just for a month or so, it’s been the whole year. I think seeing all that, how it has played out, it’s going to be a fun last month and a half.”