Taking Stock of Cubs' Pen: Who's Hot, Who's a Gamble, Who's on Thin Ice

In what's already been a rollercoaster of a season, the Chicago Cubs' bullpen is the team's most consistently productive asset.

If we go purely by ERA (3.50), it's the No. 8 bullpen in baseball. That puts them on par with some pretty impressive pitching staffs, including the New York Yankees and the Milwaukee Brewers.

Last season, the Cubs' reliever group finished right around where it is now, posting a 3.78 ERA (No. 11 in MLB).

There was some turnover in the offseason, as the Cubs lost some of their best 2025 bullpen arms in free agency. Brad Keller, who finished last year with a 2.07 ERA over 69.2 innings pitched, signed with the Philadelphia Phillies in December. Drew Pomeranz joined the Los Angeles Angels after posting a 1.94 ERA over 46.1 innings with the Cubs in 2025.

Both were under-the-radar additions before the 2025 season, and that's what President of Baseball Operations Jed Hoyer's philosophy has often been when it comes to constructing a bullpen.

But Hoyer did make one rare free agency splash on a reliever last November when the Cubs inked right-hander Phil Maton to a two-year, $14.5 million deal. We'll take a look at how that's played out in a bit — but first, let's look at Craig Counsell's most trusted arms out of the 'pen thus far:

The Top Tier

Ryan Rolison (2.25 ERA, 1.25 WHIP, 24 SO, 24 IP)

May 20, 2026; Chicago, Illinois, USA; Chicago Cubs pitcher Ryan Rolison (33) throws the ball against the Milwaukee Brewers during the seventh inning at Wrigley Field. Mandatory Credit: David Banks-Imagn Images | David Banks-Imagn Images

Rolison is having a Keller-esque resurgence with the Cubs this season.

The 2018 first-round pick of the Colorado Rockies didn't make his major-league debut until last season, where he posted a 7.02 ERA and a 1.77 WHIP over 42.1 innings in his rookie campaign.

Colorado designated Rolison for assignment in the offseason, and, after subsequent waiver claims and drops by the Atlanta Braves and the Chicago White Sox, the Cubs claimed Rolison in January.

Entering play on Saturday, Rolison hadn't allowed an earned run over his last seven appearances (9 IP), and he has just a 1.65 ERA in his last 15 games (16.1 IP).

The walk rate (12.5%) can be a bit of an issue and he does give up a lot of hard contact (46.7%), but a lot of it is on the ground and Rolison has an airtight infield defense that backs him up when he needs it.

Jacob Webb (2.76 ERA, 1.33 WHIP, 35 SO, 29.1 IP)

May 27, 2026; Pittsburgh, Pennsylvania, USA; Chicago Cubs relief pitcher Jacob Webb (71) pitches against the Pittsburgh Pirates during the sixth inning at PNC Park. Mandatory Credit: Charles LeClaire-Imagn Images | Charles LeClaire-Imagn Images

Webb, 32, signed a one-year free-agent deal with the Cubs in the offseason for just $1.5 million, and it's been another Hoyer bargain that is paying off.

The right-hander has a 1.62 ERA and an 0.96 WHIP in his last 15 appearances (16.2 IP)

Like Rolison, Webb is inducing hard contact (48.1%), which is well above his career average of 37.1%.

Still, his strikeout, chase, and whiff rates are all in the upper tier of MLB, and it makes him a reliable reliever to come in with traffic on the base paths and shut the door with minimal damage done.

Ethan Roberts (1.77 ERA, 1.08 WHIP, 16 SO, 20.1 IP)

May 27, 2026; Pittsburgh, Pennsylvania, USA; Chicago Cubs relief pitcher Ethan Roberts (39) pitches against the Pittsburgh Pirates during the ninth inning at PNC Park. Mandatory Credit: Charles LeClaire-Imagn Images | Charles LeClaire-Imagn Images

The 28-year-old Roberts is having far and away the best season of his Cubs tenure.

The Cubs' 2018 fourth-rounder got just nine innings in last season, posting a 6.00 ERA and a 1.33 WHIP.

After a finger laceration in a freak accident landed him on the IL in mid-April, Roberts has made the most of his fourth big-league season thus far. His 16 appearances and 20.1 innings pitched this year are already nearing the career highs of 26.2 innings and 21 appearances he logged in 2024.

Roberts has struggled comparatively of late (nine hits, three earned runs and two walks in his last eight innings), but he's showing what he can do in the majors with a longer leash.

Trent Thornton (2.00 ERA, 1.00 WHIP, 8 SO, 18 IP)

Jun 12, 2026; San Francisco, California, USA; Chicago Cubs closing pitcher Trent Thornton throws against the San Francisco Giants during the ninth inning at Oracle Park. Mandatory Credit: John Hefti-Imagn Images | John Hefti-Imagn Images

To say Thornton has exceeded expectations is an understatement. The 32-year-old originally signed a minor-league deal with the Cubs in the offseason, but the team selected his contract on May 6 when Matthew Boyd landed on the IL.

Thornton has allowed just two earned runs over his last 10.1 innings and is certainly earning his extended stay back up in MLB.

Thornton is no stranger to this stage — he has 419 MLB innings to his name since his debut in 2019. He's also coming off a torn Achilles that he suffered last August with the Seattle Mariners, which makes his quick resurgence even more impressive.

The Gambles

Daniel Palencia (2.87 ERA, 1.40 WHIP, 16 SO, 15.2 IP)

May 26, 2026; Pittsburgh, Pennsylvania, USA; Chicago Cubs relief pitcher Daniel Palencia (48) pitches against the Pittsburgh Pirates during the seventh inning at PNC Park. Mandatory Credit: Charles LeClaire-Imagn Images | Charles LeClaire-Imagn Images

An early-season injury (oblique strain) means Palencia's sample size is pretty small thus far. He is still Counsell's go-to closer despite some recent shakiness (4.50 ERA in his last seven appearances) and a performance in Colorado on Wednesday, which saw him fail to record an out in the bottom of the 9th before the Rockies walked it off. A slight concern is his strikeout rate being down 4.5 points at 23.9%, and there's a small uptick in his walk rate.

Even if a Palencia appearance feels like a gamble right now, the numbers suggest he'll settle into his more typical dominance soon. His fastball still sits at 99 mph, and the velocity on both his breaking and offspeed pitches is up compared to last season.

Perhaps the most encouraging sign for Palencia is his opponents' hard hit percentage, which is down a whopping 18.1% (48.5% to 30.4% from last year).

Caleb Thielbar (3.50 ERA, 1.17 WHIP, 20 SO, 18 IP)

Apr 18, 2026; Chicago, Illinois, USA; Chicago Cubs pitcher Caleb Thielbar (24) throws the ball against the New York Mets during the ninth inning at Wrigley Field. Mandatory Credit: David Banks-Imagn Images | David Banks-Imagn Images

Thielbar is, unfortunately, a victim of the regression monster since his standout 2025 campaign. In his first season with the Cubs, the southpaw pitched to a 2.64 ERA and a 0.88 WHIP in 58 innings.

The home run ball has been an early issue for the 39-year-old — he's already allowed four in 18 innings after allowing five total all last season.

A left hamstring strain in late April kept Thielbar out of action for nearly a month, but he came back to post a 2.25 ERA in May. June has been more of a rough go (5.60 ERA), but Thielbar will still likely be a solid bullpen piece for the rest of the season.

Hoby Milner (3.86 ERA, 1.15 WHIP, 15 SO, 30.1 IP)

Jun 2, 2026; Chicago, Illinois, USA; Chicago Cubs relief pitcher Hoby Milner (41) delivers a pitch against the Athletics during the seventh inning at Wrigley Field. Mandatory Credit: Kamil Krzaczynski-Imagn Images | Kamil Krzaczynski-Imagn Images

Milner got his Cubs career off to a rough start when he allowed two earned runs and hit a batter in his first two innings.

The submarine-throwing lefty proceeded to bounce back in April to post a 1.42 ERA in 12.2 innings pitched. In May, he had a 2.61 ERA in 10.1 innings pitched.

Milner did turn in his worst outing of the year on June 5 when the San Francisco Giants tagged him for six earned runs on five hits in just a third of an inning. That inflated his ERA from 2.28 all the way to 4.18, and Milner has now spent his subsequent outings trying to bring that number down.

So far, it's worked — he has not allowed a run in his three appearances since.

On Thin Ice (Kind Of?)

Phil Maton (6.17 ERA, 1.67 WHIP, 26 SO, 23.1 IP)

May 10, 2026; Arlington, Texas, USA; Chicago Cubs pitcher Phil Maton (88) throws to the plate against the Texas Rangers during the seventh inning at Globe Life Field. Mandatory Credit: Raymond Carlin III-Imagn Images | Raymond Carlin III-Imagn Images

We all know Maton isn't actually in danger of losing his job. The irony isn't lost on anyone who follows the Cubs that the reliever Hoyer finally splashed on in free agency has been the team's worst reliever by a wide margin.

The 33-year-old was coming off the best season of his career in 2025, which he split between the St. Louis Cardinals and the Texas Rangers. He pitched to a 2.79 ERA in 61.1 innings across both stints.

But Maton, for the most part, has had a disastrous 2026. A 7.71 ERA in March and a 20.25 ERA in April did not give him much to hide behind. He did hit the IL (a rite of passage for Cubs pitchers this year) with right knee tendonitis on April 10 and missed the majority of the month.

When he got more consistent appearances in May, he worked a 4.61 ERA in 13.2 innings pitched.

But there very well may be light at the end of the tunnel for Maton, who has actually been red-hot in June — he's allowed just one earned run and struck out four over his last five appearances.

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