What Can the Giants Expect From Their Young Starters?

The San Francisco Giants are heading into the 2025 season with a mixed bag of veterans and young guns in their pitching staff, making the rotation one of the key storylines to follow for the team by the bay.

The recent addition of Justin Verlander on a one-year, $15 million deal brings a future Hall of Famer into the mix, but after a neck injury limited him in 2024, there are some concerns about his health. Regardless, with Verlander taking one of the rotation slots, there will be a few young arms left to fight for the last open spot.

President of baseball operations Buster Posey has been rather vocal about trusting the young options his team has in the rotation. Despite this confidence, adding another proven arm through free agency or even the trade market could provide additional security.

The Giants boast several promising young starting pitchers who recently graduated from prospect status, offering the team depth, versatility, and plenty of competition on the mound. Here’s a deep dive into what some of the young options in the organization could bring to the table for the 2025 season.

Kyle Harrison: Can He Shake the Inconsistency?

Kyle Harrison could be seen as the crown jewel of the Giants’ young pitching options.

A little over a year removed from being perhaps the no. 1 left-handed pitching prospect in baseball, Harrison has shown some flashes of what he could be at the MLB level. Becoming the first pitcher in MLB history to throw two scoreless starts of 5+ innings at Coors Field in the same season and recording an 11-strikeout performance in just his second major league start are just two examples of that.

However, Harrison’s first full campaign in the show also exposed many areas for improvement. His 4.56 ERA over 124.1 innings to go along with a mere 8.54 K/9 and 1.30 HR/9 are indications of the inconsistency he struggled with.

To add to that, as the season progressed, his fastball velocity dipped, which could suggest he and his arm grew fatigued.

In an episode of the Giants Talk podcast, Giants’ insider Alex Pavlovic talked to manager Bob Melvin about Harrison’s ankle injury in 2024, and they both mentioned how it affected him more than fans were led to believe. This is another indication that we could see a better, healthier Kyle Harrison in 2025.

The Giants are surely counting on the young southpaw to build stamina and refine his command and arsenal to limit home runs, especially in the pitcher-friendly confines of Oracle Park. If he can rediscover the elite strikeout numbers he showed as a prospect, he has the potential to be a solid no. 3 starter – or even more.

The key for Kyle Harrison will be to maintain a higher level of consistency and finish stronger as he develops into a potential cornerstone for this rotation in years to come.

Hayden Birdsong: Raw Electricity

Hayden Birdsong had a quick rise through the system, and it became one of the more exciting storylines for the Giants in 2024. Starting the year in Double-A Richmond, he moved quickly to Triple-A and, after just nine innings, got the call to the big leagues.

His 2024 campaign showcased the raw talent he holds but also highlighted what he can work on. Over 72 innings, Birdsong held a 4.75 ERA, an impressive 11.0 K/9, but also a concerning 5.38 BB/9.

Birdsong’s arsenal is electric. His mid-to-high 90s fastball is complemented by an elite kick-changeup which held a Stuff+ rating of 155. For comparison, Devin Williams’ changeup is widely regarded as one of the best pitches in baseball, and he has a career Stuff+ rating of 160.

Pairing his fastball and changeup with a curveball-slider combo allows Birdsong to keep hitters guessing.

One area for improvement would be the usage of that changeup. Despite it being an elite pitch, the 23-year-old only used it 18.4% of the time. Increasing that pitch usage and focusing in on his command overall could make him an above-average starter in this league.

With the arrival of Verlander, Birdsong may find himself competing with Harrison or others for a rotation spot.

Our own Aram Leighton believes that Birdsong could potentially put up better numbers than Harrison over the span of a full season. Birdsong’s pitch variety and ability to miss bats could give him an edge.

Landen Roupp: A Dependable Fallback

Landen Roupp may not have had the same prospect hype as Harrison or Birdsong, but his steady performance makes him one of the more reliable options in the organization. Ranked as the Giants #12 prospect by Just Baseball during the 2023-24 offseason, Roupp uses a unique approach.

His devastating curveball, with a Stuff+ rating of 155, accounted for 44% of his pitches in 2024, which was more than his sinker. Roupp’s ability to lean on the curveball helped him post a 3.58 ERA over 50.1 innings with the big league club.

While Roupp may not crack the Opening Day rotation due to a crowded competition, his dependability makes him a strong candidate to step into a swingman role.

If injuries strike or Jordan Hicks makes the almost inevitable move back to the ‘pen towards the end of the season, Roupp’s ability to handle multiple roles gives the Giants some flexibility and could be critical in navigating a long season.

Keaton Winn: Disappointment Searching for Redemption

Keaton Winn‘s 2024 campaign was an interesting one, to say the least. Early in the year, he displayed promise and was even ranked the no. 8 rookie in all of baseball by Bleacher Report in early May.

However, things took a quick turn as the season went on. He finished with a disappointing 7.16 ERA over 55 MLB innings and an eventual season-ending arm injury in July. Winn’s struggles leave his role in 2025 uncertain, especially with so many other young arms competing for opportunities.

His best shot moving forward may be as a swingman or bullpen piece, particularly given his early-season success.

However, with Landen Roupp (and others) potentially better suited for that role, Winn will need to prove that he can stay healthy and be more effective than he was in 2024 to earn a meaningful role in the Giants’ future plans.

Mason Black: Future Trade Chip?

Mason Black‘s 2024 season also came as a bit of a disappointment. As one of the Giants’ better pitching prospects, he threw to the tune of a 5.44 ERA in just over 36 innings in the show.

Black remains prospect-eligible, and despite his struggles in 2024, he is the Giants’ no. 8 prospect according to MLB.com, so he could still hold some trade value. The Giants could look to include him in a deal to acquire another rotation piece or even a bat.

With so many internal options, it will be difficult for Black to move his way up the ranks on the rotation depth chart. This could also make him another candidate to convert to a bullpen arm at some point in the near future.

Other Names to Watch

While the Giants’ young pitching depth is headlined by the bigger names mentioned above, there are a few other intriguing arms who could contribute in 2025. These are pitchers who aren’t guaranteed significant roles, but offer the organization valuable flexibility and upside.

Trent Harris: A Breakout Candidate

Even though it would probably be in more of a bullpen role, Trent Harris was described by our own Jack McMullen as a prime candidate to break camp and make the Opening Day roster for the Giants on an episode of The Call Up podcast. He turned heads in 2024 with a dominant run in High-A Eugene.

Over the course of 45 innings, Harris posted a stellar 2.00 ERA, 12.00 K/9, and a mere 2.40 BB/9. Though he ended the year in Double-A Richmond, his clear success in Eugene indicates that he could be on the fast track to the bigs.

Harris’ command and ability to rack up Ks make him a strong bullpen option, especially if he continues his success in the upper levels of the minors. With the Giants looking for reliable bullpen depth options, could Harris be the next homegrown bullpen piece in San Francisco?

Carson Whisenhunt: A High-Upside Southpaw

Carson Whisenhunt is one of the Giants’ most exciting young arms and is the organization’s no. 3 prospect according to MLB.com. He is known for his elite changeup, which ranks among the best secondary pitches in the minors. Yet, Whisenhunt struggled with a 5.42 ERA in 2024.

However, his splits tell a unique story. He posted an impressive 2.34 ERA in home games versus a ballooned 8.31 ERA in away games, highlighting the challenges of pitching in the Pacific Coast League (PCL).

His ability to dominate with the changeup makes him a prime high-upside candidate to join the rotation in the second half of 2025. If he can adjust to higher levels of competition and improve on some inconsistencies, he could emerge as one of the Giants’ young bright spots.

Carson Seymour and Carson Ragsdale: Reliable Fallback Options

These two additional Carsons were both added to the 40-man roster in November to protect them from the Rule 5 draft. This was a signal that the Giants believe in their potential and see them possibly contributing at some point.

The righties each took on a starter’s workload in 2024, with both eclipsing the 120 innings mark. However, they did see elevated ERAs, which could be partially attributed to pitching in the Pacific Coast League, known as one of the most hitter-friendly leagues in all of the minors.

Despite some struggles, both Carson Seymour and Carson Ragsdale give the Giants decent fallback options, especially if injuries derail the trajectory of the big league rotation.

Finding a Balance

The Giants have an intriguing crop of young pitchers, but how they choose to manage some of these arms will shape their season. While Posey’s confidence in this group is encouraging, signing or trading for another veteran would provide a safety net for the aging Verlander’s health as well as the young arms’ growing pains.

Whether it’s through Harrison finding consistency, Birdsong improving his control, or Roupp becoming a dependable swingman, the Giants have ways to assemble a strong and versatile staff.

How this team balances development with immediate needs will be an interesting story to watch as the Giants look to sneak into a Wild Card spot in 2025.