SURPRISE, Ariz. -- The Astros have established themselves as one of the deepest and most formidable teams on the mound in recent years. Much of that can be credited to the immense pitching depth they possess throughout their loaded farm system. It’s a quality that has served as the foundation of an organization that has won four American League pennants since 2017.

Houston is still teeming with talented pitchers climbing the ranks, hoping to join its stable of arms sometime in the near future.

Tyler Guilfoil appears to be no exception. The 6-foot-4 right-hander was quietly one of the organization’s top performers this season, boasting high-strikeout stuff -- he punched out 34.7 percent of the batters he faced -- between Single-A Fayetteville and High-A Asheville en route to joining the elite prospect circuit this fall in the desert.

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The 23-year-old was at his best in Mesa’s 5-2 loss to Surprise on Thursday night, allowing one run on one hit and two walks in four innings. His four-pitch mix -- featuring a four-seam fastball, cutter, changeup and sweeper -- was on full display as he struck out five batters, landing 40 of his 62 pitches for strikes.

“I was not necessarily relying on the fastball, but had really good feel for the location of where I was going to throw the fastball,” Guilfoil said. “My fastball plays well up in the zone, and I was able to throw it on both sides of the plate. And then the cutter to supplement that. I was throwing it in on the lefties, and then throwing the changeup away from the lefties as well. Mixed in some changeups to the righties. Just really had control of all my pitches tonight, and being able to throw them in different quadrants throughout the night was kind of what kept the hitters on their toes.”

Guilfoil had struggled through his first four Arizona Fall League outings, surrendering 13 runs in 10 2/3 innings with 10 strikeouts. It felt similar to how he fared in five games with Asheville this year, when he posted a 4.57 ERA in 21 2/3 innings. But Thursday’s effort appeared to be a return to form for Guilfoil, who retired nine of the first 10 Surprise batters he faced.

His lone blemish came in the fourth, when Guilfoil gave up a run-scoring triple to Will Robertson (Blue Jays). Guilfoil responded by striking out Peyton Wilson (KC No. 26) on three pitches to close the book on his night.

“All the hitters here are phenomenal,” Guilfoil said. “We’ve seen that it’s a hitters' league, and I felt like I executed our game plan to each guy and pitched to my strengths but also their weaknesses a little bit.”

The key to his success since his college days as a dominant reliever at Lipscomb and Kentucky has been his fastball, which Guilfoil claims has always been his best offering. He still leans heavily on that pitch, particularly up in the zone, but since transitioning to a starting role, Guilfoil has prioritized broadening his repertoire.

“In college, the fastball was my best pitch,” he said. “I was very fastball-dominant. In college and getting into pro ball, I had to add some pitches. I added the sweeper and I added the cutter. Developed the changeup a little more, but had that in college. Being able to have a four-pitch mix now is very helpful to keep hitters on their toes and get weak contact where I need to and try to get strikeouts where I need to as well.”

An eighth-round pick by the Astros in 2022, Guilfoil has always excelled at striking batters out. He punched out 205 hitters across his four-year collegiate career, including a career-best 80 in his final year at Kentucky. The righty posted a miniscule 1.59 ERA across 51 innings in 2022, a performance which earned him First-Team All-Southeastern Conference honors.

Guilfoil continued to stay true to that high-strikeout profile in his debut campaign last year, spent primarily in Fayetteville. He finished with a 0.52 ERA in 17 2/3 frames, whiffing a whopping 50 percent of batters he faced before following it up with a 3.21 ERA and 123 punchouts in 84 innings in his first full pro season this summer.

He has a long way to go and plenty left to prove before joining the Astros' loaded pitching arsenal, but if his performance on Thursday is any indication, Guilfoil is on the right track.

“[The Astros] create a great culture of guys that are all trying to get better, and with that, it’s hard not to get better,” he said. “And with all the technology we have now, you can really dive into what your deficits are and get better. I just try to get better every time I go out there.”