3 Starting Pitcher Breakouts: Who's For Real?

Andy looks at 3 starting pitcher fantasy baseball breakouts, sleepers off to hot starts in 2025. Are Reese Olson, Matthew Liberatore and Will Vest for real?

Even though we are just a month into the fantasy baseball season, several pitchers have enjoyed the best start to a season they have ever had. However, it is crucial for fantasy managers to determine if these breakouts are legitimate and if they could ultimately become league winners.

In this piece, we will do a deep dive on three pitchers who have surprised many through the early part of the campaign: Detroit Tigers right-handed pitchers Reese Olson and Will Vest, and St. Louis Cardinals left-handed pitcher Matthew Liberatore.

Should fantasy managers run to the waiver wire to add these breakout pitchers? Or are they fool's gold? Let's dive in!

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Reese Olson, Detroit Tigers

2025 Stats: 33 IP, 3.55 ERA, 3.82 SIERA, 1.24 WHIP, 23.4% K%

47% Rostered

Reese Olson logged over 100 innings in the major leagues during each of the previous two seasons but often saw mixed results. Across these two years, the right-hander has held a modest 3.75 ERA with a 1.15 WHIP across 216 innings of work. During this stint, Olson had tallied 204 punchouts (23.1 percent strikeout rate) and served up 66 walks (7.5 percent walk rate).

However, it appears the former 13th-round pick has taken the next step forward in his development early in the 2025 season. After allowing 10 earned runs through his first 15 innings, Olson has flipped the script, logging an impressive 1.50 ERA with a 0.89 WHIP across his last 18 innings (three starts).

During this impressive three-game stretch, Olson has tallied at least seven punchouts in two starts and did not allow a run in two games as well. In addition, during this stretch, he did not allow a long ball.

The primary reason Olson's strikeout rate climbed (in relation to his 2024 production) is due to his changeup. In 2024, Olson relied on his changeup 22.3 percent of the time, which was his third-most-used pitch. The pitch was successful as it generated a solid 42.9 percent whiff rate with an impressive .281 xSLG and a .251 xwOBA.

Reese Olson, Dirty 86mph Changeup. 👌

6th K pic.twitter.com/3StdioLFA3

— Rob Friedman (@PitchingNinja) April 30, 2025

However, the North Hall HS product has begun to lean on this pitch even more, and it has been a driving force of his early-season success. Throughout the opening month of the campaign, Olson has seen his changeup usage climb to 26.1 percent, and it has found even more success. This pitch has generated an eye-catching 50.0 percent whiff rate with a stellar .153 xSLG and a .139 xwOBA.

In his best outing of the season (his seven 1/3 inning gem against the Padres on April 23), his changeup led the way as it generated nine whiffs.

However, while his changeup could suggest a breakout is on the way, his other pitches have not enjoyed as much success. After only using his sinker 20.0 percent of the time in 2024, it has become his most-used pitch in 2025. This pitch has generated a modest .515 xSLG with a .423 xwOBA, much higher than the .368 wOBA it currently carries.

Verdict: While his changeup has shown the potential to produce excellent results, Olson will need to further develop his sinker to achieve more consistency. In his most recent outing, he has already begun to regress as he allowed three runs and four hits across five 2/3 innings. He is still a viable depth SP4/SP5 in standard formats, but do not expect elite results.

Matthew Liberatore, St. Louis Cardinals

2025 Stats: 31 IP, 3.19 ERA, 3.04 SIERA, 0.97 WHIP, 23.1% K%

28% Rostered

Once considered a top pitching prospect, Matthew Liberatore has yet to put it all together at the major league level. Entering the 2025 season, the southpaw posted a 4.99 ERA with a 1.43 WHIP over his first three MLB seasons (182 1/3 innings). He struck out just 150 batters and showed weak command of his pitches as he served up 71 free passes.

However, the former 16th overall pick has made some adjustments in the opening month of the 2025 campaign and appears to be enjoying a post-hype breakout season. Through his first 31 innings, Liberatore has held an impressive 3.19 ERA with a 0.97 WHIP. During this stint, he has struck out 28 batters and allowed just two total walks.

The first glaring improvement is his control. Entering the 2025 season, Liberatore held a cumulative 9.4 percent walk rate over his first three MLB seasons. However, this season, he has walked batters at a near-perfect 1.7 percent rate. In addition, he also holds a career-high 23.1 percent strikeout rate. This is a two percent increase compared to his production in 2024.

So, what is driving this breakout? For the first time in his career, Liberatore has relied on his slider as his primary pitch, and it is benefiting him significantly. During his first three seasons, Liberatore threw his fastball as his primary pitch and relied on his slider only 17.0 percent of the time, on average.

Over his last 3 G, Matthew Liberatore has leaned heavily on his slider, making it his primary offering

Hitters counts, first 2 G v last 3:
SL%: 15.4% ➡️ 29.3% 📈
SLWhiff%: 25.0% ➡️ 44.4% 📈
FFSink%: 59.0% ➡️ 39.1% 📉

He added a tick in SL velo while sacrificing just 1" of depth pic.twitter.com/eJvdI2pcF8

— Jacob (@JacobE_STL) April 26, 2025

However, this season, he has thrown his slider 28.7 percent of the time. This pitch has generated a 36.7 percent whiff rate and a 25.0 percent put-away rate. In addition, it boasts an impressive .299 xwOBA. By relying on this pitch more often, his fastball usage has dropped to a career-low 25.3 percent.

While this pitch has generated a modest .273 BA with a .326 wOBA, according to Statcast, it has generated a much lower .233 xBA and a .277 xwOBA, which suggests the southpaw may even see further positive regression.

Verdict: Given his well-improved command and increasing reliance on his slider, Liberatore has put himself in a great position to enjoy a career season. He should be rostered in all standard formats as he appears to be a strong asset when looking to improve your WHIP ratio.

Will Vest, Detroit Tigers

2025 Stats: 2.77 ERA, 2.97 SIERA, 1.00 WHIP, 27.5% K%

27% Rostered

Despite pitching in a crowded Detroit bullpen, Will Vest has emerged as a reliable high-leverage option. Over his first 12 innings of the campaign, Vest allowed just one run and held an impressive 0.58 WHIP with three saves. During this strong start, Vest tallied 14 punchouts and served up just four walks.

However, his ratios became a bit inflated on Tuesday evening when he allowed five hits and three runs across one inning of work.

However, despite this rough appearance, Vest carries strong underlying metrics that suggest he could be in store for a career season in 2025.

Through his first 13 innings, the right-hander has placed in the 94th and 95th percentile with a 2.14 xERA and a .175 xBA. In addition, Vest has generated whiffs at an elite 33.0 percent rate (89th percentile) and groundballs at a 59.4 percent rate (93rd percentile).

Vest relies heavily on his fastball (59.2 percent usage rate) and mixes in a slider (21.9 percent usage rate). In comparison to his 2024 results, where he posted an overall 2.82 ERA with a 1.12 WHIP, both of his most frequently used pitches have shown signs of further improvement.

While the sample size is small, his fastball has seen its whiff rate increase by nearly 10 percentage points (22.9 - 31.7). This pitch has also generated a .174 xwOBA, a much better mark compared to the .289 xwOBA it generated in 2024.

His slider whiff rate has increased substantially, boasting a 61.1 percent whiff rate through the early part of the campaign, compared to the 29.7 percent rate it generated in 2024.

Will Vest ends opening day with a strikeout for the win. Dan Dickerson on the call #RepDetroit pic.twitter.com/aYg0jiSs0Q

— Dan Dickerson Calls📞 (@dannydHRs) April 4, 2025

Verdict: As stated above, as a relief pitcher, his current sample size is quite small, and fantasy managers should not react especially to his much higher whiff rates. However, his underlying base metrics, like xERA and xBA, suggest that the 29-year-old could be in a position to enjoy a breakout campaign. In leagues that reward both holds and saves, Vest should be viewed as a must-add.

In standard leagues that only value saves, Vest carries slightly lower value as he will likely be competing alongside Tommy Kahnle for most of the shares. Even if he only finishes the season with low-double-digit saves, his elite ratios will still provide value, but not as much in saves+holds formats.

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