The last two seasons have been filled with MLB debuts for Colorado Rockies pitchers, including a trio of young relievers who have made an impact late in games: Seth Halvorsen, Zach Agnos and Juan Mejia. Halvorsen debuted in August 2024, while Agnos and Mejia both debuted in 2025.
Of the three, Mejia made the biggest splash in 2025, ranking eighth in our “Ranking the Rockies” series, and is currently playing for the Dominican Republic in the World Baseball Classic. But all three are making their cases
for why they should start 2026 with the team after taking some big lessons from last season.
Lessons learned in 2025
“I think the biggest lesson that I learned [in 2025] is that I’ll always be able to make adjustments,” Halvorsen said. “I think that I’m always wanting to make adjustments and improve, whether it’s game to game, year to year, pitch to pitch – I just want to be able to consistently make adjustments going forward.”
Mejia echoed that, while also leaning on his faith.
“Every mistake that I had, I can learn from that,” Mejia said through interpreter Edwin Perez. “Without any mistakes or errors, you can’t really grow as a player or you can’t learn. So I think I just grew overall learning through all the things that I went through last year.”
For Agnos, the lesson was different.
“Just being in the strike zone, honestly,” he said.
“When I was throwing really well, I was throwing a ton of strikes. And then when I wasn’t throwing so well, I didn’t throw a ton of strikes. And that’s been kind of the emphasis this camp and my bullpens and my live [BP’s] and from Alon [Leichman] and Gabe [Ribas] and Matt [Daniels] and [Matt Buschmann] and [Warren] Schaeffer and Paul [DePodesta] – everybody top to bottom, ‘Just throw strikes!’ I believe in my stuff. I believe I have the stuff to be an everyday guy, so now it’s just putting it over the plate and making hitters earn it.”
Throwing strikes and getting ahead in counts early has been an emphasis of the newly revamped coaching staff, and something Schaeffer has preached throughout camp.
Something else that has permeated Rockies camp since the new coaches were hired is an increased arsenal. Ryan Feltner added a cutter; Chase Dollander added a sweeper; and Kyle Freeland has been tweaking his changeup.
New pitches incoming
And just like the starters, the relievers are adding to their arsenals, too.
For Halvorsen, the work started in the offseason with his fastball and slider.
“I switched the grip [on my fastball] a little bit to maybe make it a little more true,” he said,” and then I switched the grip of my slider for it to maybe have a little more depth, or at least have the ability to do that. And then maybe I’ll manipulate that pitch a little bit, so I’m excited with those two for sure.”
Mejia, like Freeland, is working on his changeup and slider.
“I didn’t have the biggest confidence in it last year, and that’s why I didn’t throw it,” he said. “So that’s my pitch that I’ve held back, but I think I’m truly growing into it and getting better at it. And the slider – I think the slider’s still the same, but in a sense, it’s getting better. I’m just improving that.”
Agnos, on the other hand, is adding a plethora of new pitches.
“Sinker and curveball, and then we’re tweaking with my cutter, sweeper and slider,” he said during the first weekend of spring training. “I was actually with my brother (Jake) in the offseason. He gave me a lot of helpful little tips and showed me some grips that I talked to Alon and Gabe about, and the sweeper has been good. So it’s kind of nice to have these guys as pitching coaches and my brother as a pitching coach. You get two sets of eyes.”
Additionally, as of Saturday, Agnos has added yet another pitch at the suggestion of Michael Lorenzen.
“It’s called a death ball,” he said.
“It’s an interesting pitch. I threw it against Team USA, so it’s pretty good, but I’ve still got a lot of room to grow with it. But it’s been fun!”
The new coaching staff is really helping
And, of course, they’re learning a lot from the new pitching coaches overall.
“They’ve all been super fantastic. They’ve been awesome,” said Agnos.
“They communicate a plan, whether I’ve wanted to hear it or not. They’ll tell you how it is and it’s awesome. There’s a clear plan, and they’re definitely trying to develop us, which is awesome.
“[It’s] the most fun I’ve had playing catch,” he continued. “As stupid as that sounds, I’ve never had so much fun playing catch. Like today (Feb. 15), I threw with Alon because he wanted to work on my sweeper and cutter. So it was good, and he got to see it firsthand. We had a good talk, and he’s kind of building up some confidence in us, which is good, too. He just kept being like, ‘You’re nasty, bro, you’re nasty. Trust [yourself].’ He’s like, ‘You’re nasty.’ So it’s cool to hear. It’s always nice to hear – I believe it – but it never hurts to hear.”
For Halvorsen, it was an immediate change in his slider.
“I’ve done the same pitch there for a couple years now,” he said, “and then right away they came in and they had me make that adjustment. And I saw results – beneficial results – right away. So it was pretty exciting to see that.”
Mejia is noticing the difference in the clubhouse.
“It’s been very positive overall,” he said. “They’ve helped me so much already. From the start, you can feel that there’s a different energy, a different atmosphere in here, and I think that’s going to help us a lot this year.”
“I think we can have a better record this year,” he continued. “I think we can play better as a team and hopefully these changes bring us to the championship one day. Hopefully this year, and hopefully we’re able to celebrate this year, but more than anything, I think it’s been overall a great adjustment for all of us.”
Schaeffer had nothing but glowing things to say about the trio.
“All three of those guys are dudes. There’s no doubt about it” he said. “The one that has been the most impressive in camp, for me, has been Agnos with the way he’s attacked the zone and pounded it, doing what we’ve been asking 100%. It’s been impressive.
“Mejia, also, is one of our top guys. He’s so nasty. So it’s been a good progression for him,” he continued. “And it’s been a good progression for Seth. Seth’s working on new things, and so is Juan. So it’s about striking that balance, about executing the fundamentals in game, pounding the strike zone, and working on stuff, which is difficult early in camp. So I don’t foresee any problems.”
Closing thoughts
Agnos has been lighting it up in spring training, making a very strong case for the Opening Day roster. Halvorsen has been tinkering with things, but his fastball command has been improving. And Mejia has been outstanding for Team Dominican Republic in the World Baseball Classic.
2026 is still up in the air for a lot of Rockies, but at least the bullpen appears to be a strength heading into it.
To Read (Rockpiles)
- Monday: Rockies first baseman T.J. Rumfield looks to contribute | Renee Dechert
- Tuesday: Cole Carrigg takes being a ‘super-utilityman’ seriously | Sam Bradfield
- Wednesday: The Rockies may be solving fastballs on offense | Skyler Timmins
- Thursday: The potential impact of dugout pitch calling | Cory Cohen
- Friday: ‘Real arms coming’: A glimpse into callups and which Rockies pitchers might soon make their debuts | Joelle Milholm
- Saturday: Why Rockies spring training feels different this year | James Riggenbach
To Read (PuRPs)
To Read (State of the Position)
- Ownership: Colorado Rockies ownership, change, and hope | Adam Peterson
- Front Office: Paul DePodesta and Josh Byrnes have ushered in a new day | Renee Dechert
- Manager & Coaching Staff: Warren Schaeffer has assembled a data-driven team of problem solvers and relationship builders | Sam Bradfield
- Starting Rotation: The Rockies’ rotation features new faces, but is it better? | Cory Cohen
To Read (Other)
- Staff Feature: Nolan Arenado remembers his time with the Colorado Rockies as he returns to the NL West | Sam Bradfield
- Roster News: Rockies 2026 Spring Breakout rosters announced | Cory Cohen
- MLB Previews: National League East 2026 Preview | Zeke Perez
Weekend Discussion Topics
Who has impressed you so far in the WBC? Who has impressed you so far in Rockies spring training? Let us know in the comments!
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