Unheralded Cubs Relief Pitcher Is Team's Best Kept Secret

The Chicago Cubs look to be one of the strongest teams in baseball this season, but they still have some weaknesses that have to be addressed to remain a contender.

Pitching is their No. 1 need currently, with injuries and ineffectiveness ravaging the staff.

Their two best starting pitchers -- Justin Steele and Shota Imanaga -- sitting on the injured list is tough to overcome. In the bullpen, the team has received underwhelming production again, similar to 2024.

However, things have started to settle down in the relief pitching staff with the additions of veterans Chris Flexen and Drew Pomeranz.

Toiling in the minor leagues with the Cubs and Seattle Mariners, respectively, both players have provided an incredible boost at the Major League level.

Flexen has yet to allow a run in 14.1 innings of work since being promoted from Triple-A Iowa and Pomeranz has thrown 13.2 shutout innings, resulting in both players getting moved up the pecking order of manager Craig Counsell.

That duo’s success wasn’t being counted on coming into the year, but it also isn’t the most shocking development for Chicago since they have experienced success in the big leagues previously.

Don't forget about Brad Keller, who has been productive as well out of the bullpen after struggling in 2024 with the Chicago White Sox and Boston Red Sox.

Who has surprised the most for the Cubs this season is Caleb Thielbar, who was named the team’s best kept secret in 2025 by Tim Kelly of Bleacher Report.

Caleb Thielbar Has Provided Cubs With Unexpected Great Production

“At 38 years old, Caleb Thielbar is easily the oldest player to appear on this list. But after eight seasons with the Twins, he seems to have found something in his first campaign with the Cubs,” Kelly wrote.

The veteran lefty has become an integral part of the late-game equation for Counsell, being called upon to pitch the seventh inning nine times out of his 25 appearances.

He has done a wonderful job, recording six holds thus far with a 2.05 ERA in 22 innings of work. Thielbar has yet to surrender a home run, doing a wonderful job of limiting hard and damaging contact by missing barrels.

Don’t expect the production to slow down any time soon, since Thielbar has an xERA and xBA in the 98th and 99th percentiles of baseball.

What was once viewed as a weakness for the Chicago is quickly turning into a strength.

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