Eight years ago, reliever Caleb Thielbar thought his professional baseball career was over.
Coming off his second season playing in an independent league at 30, a pathway back to a major-league team’s affiliate let alone returning to the majors felt like a long shot. The left-hander figured his 2017 season would be his last. Fortunately, the Detroit Tigers saw some potential in Thielbar after he put up a 2.40 ERA in 86 1/3 innings during his two-year stint with the St. Paul Saints in the American Association.
The Tigers gave him an invitation to spring training in 2018, though he didn’t make the team out of camp and would spend the first 1½ months in extended spring training, a dubious spot.
“At that point, I was willing to do basically anything to get back into an affiliate position,” Thielbar recalled to the Tribune. “I was kind of their guy that year that bounced back and forth between Double A and Triple A, depending on who needed the spot.”
Thielbar pitched well for the Tigers at Triple A in 2019 but again was a free agent heading into 2020. By then, he was 32 and hadn’t pitched in a major-league game in more than four years.
“It’s one of those things where it’s like, if you can’t get back up by that point, how are you going to get back?” Thielbar said.
He knew there was a real possibility that chance wouldn’t come. But the Minnesota Twins, with whom Thielbar had spent five years in their organization including three in the majors, believed in what he had shown in the minors the previous year and brought him back for the 2020 season. Thielbar shined in the shortened season and rejuvenated his career in the ensuing five seasons with the Twins.
Now 38, Thielbar has become a valuable piece in the Chicago Cubs bullpen after signing a one-year, $2.75 million contract in December.
“There was just a drive in me to be able to try to get back to to that feeling, and it took a long time, but I did end up getting there,” Thielbar said. “I’m thankful to be where I am now, but if things wouldn’t have worked out, I guess I would have been happy with how it ended there.”
Thielbar’s 1.99 ERA is the 11th-lowest among MLB relievers while only 14 National League relievers have posted a better fWAR than his 1.1, including closer Daniel Palencia (1.2). Thielbar’s 191 ERA+ and 0.826 WHIP lead the Cubs bullpen. He ranks third in innings pitched (49 2/3) among their relievers behind Brad Keller (61 1/3) and Palencia (50).
Cubs reliever Caleb Thielbar delivers against the Red Sox on July 20, 2025, at Wrigley Field. (Eileen T. Meslar/Chicago Tribune)
Thielbar is known for his meticulous note taking and game preparation, a habit that began early in his career when team-provided data and information was not near the level it’s at in today’s game.
“The veteran in him that knows what he does really well and then is uber prepared gives him a lot of confidence to go out there and compete and do whatever in any situation we put him in,” pitching coach Tommy Hottovy said. “For me, the most impressive thing is we knew he’s going to be really good against lefties, but what he’s done to neutralize some really good righty pockets, too, with the way his fastball plays and the curveball plays off of it, have been really good.”
Thielbar is coming off the worst season of his big-league career when he posted a 5.32 ERA and 78 ERA+ in 59 appearances for the Twins. Reflecting on the season, Thielbar is in a much better spot mechanically than a year ago, describing his delivery as clunky, and his arm has regained the whippy action it needs for him to be successful.
“I thought it was maybe just getting a little too old, body just won’t allow me to do it anymore,” Thielbar said. “I just need to do the right things now. It’s not so much about getting stronger all the time and just stretching, there’s just different different movements that I do, a lot of breathing exercises, and it really opens up the body to allow that movement.”
The quality of stuff has made a jump this year. His fastball has more life, he can throw his curveball in the zone when he wants to, and being able to incorporate his harder-thrown slider gives him a true third pitch versus righties. Thielbar calls his slider an equalizer. After throwing just seven sliders in 2024, he has increased the usage to 11.5%, with 45 of the 82 going to right-handed hitters.
“I just didn’t have that fastball last year, if I was throwing a fastball in a fastball count, it was going to be waxed,” Thielbar said. “Honestly, it’s kind of all three blended together just in different ways. But it’s been a lot more fun this year than it was last year.”
Thielbar has become one of manager Craig Counsell’s go-to relievers in the late innings when the Cubs are trying to keep the game tied or maintain a lead. The consistency the Cubs have received from their high-leverage relievers has at times been an unheralded part of their success. Drew Pomeranz, Keller, Thielbar and Palencia all have an ERA that sits under 2.45 with each of them appearing in at least 47 games.
Knowing he has at most only a couple of years left in his career, Thielbar has been soaking in what has been a memorable first season in Chicago.
“It’s the wonderful thing about pitching, you don’t hear that story about position players,” Counsell said. “But pitching is different from that spot, and you can really improve later in life with whatever: health, strength, a new pitch, a different grip. It can change really fast, and that’s why you stick with it, and often that’s why you see guys lasting a long time.”