The Cubs’ 2024 campaign is a prime example of the unpredictability of bullpens.

When the season began, they felt good about their options — Adbert Alzolay was slotted as the closer, Julian Merryweather and Mark Leiter Jr. were back in the fold and Héctor Neris and Yency Almonte were veterans that would augment that group.

But over the first two months of the season, injuries and ineffectiveness made the Cubs’ bullpen more of a worry than a strength.

“Bullpens are volatile,” Cubs general manager Carter Hawkins said. “I think that’s something we knew coming in.”

The group, though, has been stabilized over the last month-and-a-half or so. Part of that is the addition of new faces like Tyson Miller (1.47 ERA, 0.75 WHIP in 29 games) and Jorge López (0.48 ERA, 1.23 WHIP in 16 games), who were designated for assignment by the Mariners and Mets, respectively. Another part of that is just general internal improvement and stabilization.

Porter Hodge was promoted from the minors, probably before he was even ready to be a big leaguer and is picking up key outs for the Cubs. The Cubs worked with Miller and Neris to improve throughout the course of the year. Miller has gone from being let go by Seattle to a key reliever and Neris has cut his walk rate from 16.4% through July 1 to 8% since.

“You can’t sell short the work that our bullpen guys have gone through and our coaches to make sure that our attack plans are right, and making sure that any adjustments they can make to get more outs are happening,” Hawkins said.

Since June 27, the Cubs’ bullpen has a 1.69 ERA — the best mark in baseball in that time by a full run — and a 1.02 WHIP that is also tops. The Cubs’ relief corps has steadied to the point where it feels on any given night, manager Craig Counsell has plenty of options at his disposal.

Neris has settled into the closer’s role, and his veteran experience allows him to maneuver in that role. Hodge and Miller are trusted leverage arms. Drew Smyly is a bit of Swiss Army Knife, used in matchups against lefties, long relief or leverage situations.

López is seemingly in Counsell’s circle of trust. Merryweather, one of the Cubs’ most trusted relievers last season, is pitching in close games — usually when behind — showcasing the depth of the bullpen.

Nate Pearson and Ethan Roberts, the final two relievers in the Cubs’ bullpen, showcase intriguing stuff. Pearson has a 0.68 ERA in 7.1 innings since being acquired from Toronto and has been working on adjustments that both sides hope can help unlock even more.

But if there’s one thing the Cubs have taken away from their bullpen construction this year it’s that volume helps. It creates a larger margin for error for the inevitable underperformances or injuries that happen. It allows other arms to rest and not be burnt out, like what happened in 2023.

The last few weeks have showcased what some buffer zones can do — and the Cubs hope they have that moving forward.

“Bullpens are just going to have some ups and downs,” Hawkins said. “And just got to continue to raise your bar so that when those ups and downs happen, it doesn’t have as negative an impact.”