MINNEAPOLIS -- Caleb Thielbar has about as discerning, self-aware, candid and thoughtful of a baseball mind as there is in the Twins’ clubhouse.

That’s why he’s been able to resurrect his career in his late 30s following a four-year absence from the Majors to find a very late prime as one of Rocco Baldelli’s most trusted relievers -- but that’s also why this extremely tough start to the 2024 season is weighing so heavily on him, especially as he finds no answers.

The toughest season of Thielbar’s career continued when he was tagged for four runs in the sixth inning of what had been a scoreless game against the Rockies on Tuesday, with the bulk of the damage coming on a three-run blast by Ezequiel Tovar that sank the Twins into too deep of a hole, denying a late comeback bid in a 5-4 loss at Target Field.

“My stuff sucks. The process sucks. Everything just sucks,” said a very raw Thielbar. “I really don't know what to say. I'm trying.

“It's just been a battle. I don't know. I'm doing everything I can. It's just that nothing seems to be working.”

Self-evaluation of relief pitching is difficult because it’s such a high-variance craft that even a handful of bad early outings strung together can lead to ugly-looking stats. Thielbar has overcome plenty of that in pitching to a 3.21 ERA in 179 appearances across the last four seasons -- typically in very high-leverage spots.

After Tovar’s homer and the runner he left on second that came around to score against Cole Sands in that sixth, Thielbar’s ERA is up to 7.47 in 22 appearances this season.

“It isn't just a one-game blip at this point,” Thielbar said. “Yeah. I don't know. I have about one more idea.”

Thielbar is attuned enough to his game and what makes him an effective pitcher to understand that there does appear to be something truly amiss under the hood. He knows, for instance, that his high-carry fastball -- the pitch around which his entire arsenal is predicated -- has lost 1.2 inches of carry (or perceived rise, if you want to think of it that way) on average, since 2020.

“At least [that much],” Thielbar said. “Yeah. Maybe more. But I’ve had some ideas. But nothing seems to come to fruition when I try it. Keep looking. Keep searching. Hopefully keep getting chances. I don't know.”

That’s so important to Thielbar’s success because that’s why his fastball plays so well despite averaging only 92-93 mph even at its best. When it carries, or “rises,” batters tend to swing underneath it, popping it up or missing it altogether.

His swing-and-miss rate on the fastball is down by half since 2022 -- from 29.6% to 14.5% this season, despite the average velocity actually being up this season. Opponents are hitting .325 against the fastball this year, and Tovar’s homer came against a fastball that often wouldn’t have drawn such squared-up contact when the pitch has been at its best.

“The velo is better, but the movement is terrible,” Thielbar said.

Thielbar said he’s been racking his brain for hours at a time, day after day, trying to get that fastball carry back, because that’s what allows his arsenal to work.

He’s been watching hours of video trying to find an easy fix, he said. He’s messed with grips, arm actions, mechanical tweaks, the “whole kitchen sink,” as he put it.

Does he feel any closer to finding it?

“No,” Thielbar said. “I feel farther away than ever. But all it takes is one good day to kind of get back to where I need.”

The simplest explanation -- and perhaps what Thielbar might be afraid of -- is that he’s 37 years old, having hit his prime very, very late. He’s aware of his age, his salary and the fact that the Twins not only have lefty reliever Steven Okert pitching in bigger spots, but also another fully-formed lefty in Kody Funderburk incubating in Triple-A.

“I think he’ll work and make adjustments like he always does,” manager Rocco Baldelli said. “We believe in him. He’s a good pitcher.”

But Thielbar is definitely feeling the pressure.

“I keep costing us games over and over and over,” Thielbar said. “We don't really have that leeway right now. So that weighs on me quite a bit. At the end of the day, hopefully, guys continue to…”

He paused.

“Hopefully, they actually believe in me, and it's not just lip service,” he added.