3 Starting Pitcher Breakouts: Who's For Real?

Dan looks at 3 starting pitcher fantasy baseball breakouts, sleepers off to hot starts in 2025. Are Mitchell Parker, Andrew Heaney and Landen Roupp for real?

Finding reliable starting pitching can be difficult, whether that's through the draft or during the season, off the waiver wire. But just try to win a fantasy baseball league without good starting pitching - it's nearly impossible.

We are a month into the season, so most starters who debuted in March have four starts under their belt by this point. Whether some of the pitchers you drafted have underperformed or have been forced to the IL with an injury, it's quite likely that you are in the market for another reliable starting pitcher one way or the other.

In this article, I am going to break down three starters who have pitched above expectations for the first month of the season to see if they are worthy of a roster spot on your team. These pitchers are all rostered in fewer than 40 percent of Yahoo leagues and could be available on your waiver wire. Let's analyze which pitchers are for real and which of them might be fool's gold.

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Landen Roupp, San Francisco Giants

2025 Stats: 22 IP, 4.09 ERA, 2.98 SIERA, 1.36 WHIP, 31.2% K%

35% Rostered

Roupp was a dark horse to make the rotation out of camp, but was able to beat out the more experienced lefty Kyle Harrison and fellow righty Hayden Birdsong to start the season as the Giants' fifth starter.

Roupp made his MLB debut in 2024, tossing 50 frames, mainly as a reliever, but also made four starts and compiled a 3.58 ERA and 1.37 WHIP. Walks were an issue last season as he finished with a 12 percent BB percentage, and he was quite average in strikeouts with a 21.7 K percentage and 10.3 SwStr percentage.

But 2025 has been a very different story so far. Roupp has been missing bats and elite rate (16.6 SwStr percentage), which has led to a 31.2 K percentage. He has eight or more strikeouts in three of his four starts this year, and two of those performances came against good teams (PHI and HOU).

His command remains a concern, and as a young pitcher, he is still a work in progress. The walks are down, though, as his BB percentage is at 8.6 and his ERA is a bit overinflated based on a .358 BABIP and 23 percent HR/FB percentage. His SIERA of 2.98 and xFIP of 2.83 both suggest that he will be better than a 4.00 ERA pitcher.

As you can see in his movement profile, Roupp is getting excellent horizontal movement on his three primary pitches - his sinker, changeup, and curveball.

4) Landen Roupp - SFG

Roupp has been striking batters out at an elite clip, and his curveball is a big reason why. He locates is consistently in the bottom of the zone which induces some nasty swings. His sinker gives him a stable floor while his changeup and cutter look solid. pic.twitter.com/9QwZUYnFo0

— Thomas Nestico (@TJStats) April 21, 2025

His curveball has been particularly nasty. He is getting 19 inches of glove-side run on the pitch, and it's been a fantastic out pitch for him with a 56.8 percent whiff rate and 38.5 percent put-away rate. He's been destroying righties with a 36 percent K percentage so far while still being relatively effective against lefties (21 percent K percentage) with the cutter instead of the changeup as his third pitch.

Verdict: Roupp has flashed impressive strikeout ability that isn't usually available on the waiver wire. He has a strong profile, as what he lacks in velocity, he makes up for with above-average movement. The curveball has been elite, and the Giants have a reputation for developing pitchers. This is a young pitcher with upside and is easily worth a speculative add to see if he can keep up the high strikeout rate while bringing down his ERA and WHIP numbers. ADD IN ALL FORMATS!

Andrew Heaney, Pittsburgh Pirates

2025 Stats: 31.1 IP, 1.72 ERA, 3.08 SIERA, 0.77 WHIP, 26.3% K%

41% Rostered

He did it again! If there was any doubt as to whether Andrew Heaney is back and ready for a late-career resurgence, they were answered last night as he was nearly perfect against the Angels, striking out nine hitters and allowing just one hit over six strong frames.

Andrew Heaney tonight:

6.0 IP, 1 H, 0 R, 0 BB, 9 SO
95 pitches, 66 strikes, 17 (!!!) whiffs

Absolute masterclass. He now has a 1.72 ERA. pic.twitter.com/eK4XAh5ezA

— Platinum Ke’Bryan (@PlatinumKey13) April 24, 2025

Heaney lowered his ratios in a big way while raising his strikeout rate to 26 percent. We haven't seen those types of numbers from Heaney since his 2022 season with the Dodgers, when he had a 3.10 ERA and a 35 percent K percentage.

Now the skeptic in me, you know - the guy who spent years stacking against Heaney in DFS contests and the guy who always believes the Pirates tend to ruin free agents, not fix them - was immediately looking for some numbers to suggest that this start for Heaney is a fluke. And yes, a .229 BABIP is not sustainable as well as an 81 percent strand rate (which would be the best of his career).

However, there are some good signs here, too, when looking under the hood at his underlying metrics. The walk rate is just 5.1 percent, and Heaney's hard contact rate is down to just 31.6% with a barrel% of only 6.3%. He's inducing weak contact and avoiding the home run more often.

As we can see in the chart, Heaney has been tinkering with his pitch mix over the last five seasons, and he has made a significant change this year so far. As his average fastball velocity continues to decrease (he's now down to around 90 mph), he has reduced his fastball usage while increasing his changeup usage and replacing his slider with a curveball as his primary breaking pitch.

Going changeup-heavy has worked well as the pitch has an excellent .136 xBA. The curveball doesn't have great movement, but he can throw it with velocities ranging from 78 mph to 72 mph, providing a variety of pitches to show hitters.

Verdict: While there's no guarantee he can continue this elite run prevention, Heaney has always been a crafty lefty with strikeout potential. His new home park at PNC Park is very friendly to LHP with a spacious left and center field, and Heaney has improved his control and groundball rate. He doesn't have the same ceiling as Roupp, but could be a very usable asset in fantasy given his track record. I think he's a strong pickup in nearly all formats.

Mitchell Parker, Washington Nationals

2025 Stats: 1.39 ERA, 4.76 SIERA, 0.93 WHIP, 15.6% K%

40% Rostered

Parker has been a major surprise this season that I'm not sure anyone saw coming. He made 29 starts as a rookie last season and finished with a very mediocre 4.29 ERA and 1.30 WHIP. While it makes sense that he's taken a step forward, he's been much better than anyone could have expected, at least in terms of run prevention.

Mitchell Parker lowers his ERA to 1.39 with 8 scoreless innings for the victorious @Nationals. pic.twitter.com/WGBSPKNWeN

— MLB (@MLB) April 23, 2025

Parker's profile doesn't impress me too much, so I am finally going to pour some cold water on a pitcher in this piece. He's very fastball-heavy and getting away with a 92 to 93 mph fastball because of some above-average induced vertical break. But none of his secondary pitches get great movement, and we can see from the movement profile that his pitches are more clumped together than we see with better pitchers.

He has an extreme over-the-top delivery with a sixty-degree arm angle that helps him keep the ball down in the zone, but it also really limits the horizontal movement on his pitches.

His SIERA of 4.76 is alarming, and his xFIP of 4.56 also suggests that his incredibly low ERA is unsustainable. He's striking out just 15.6 percent of hitters (down from 20.6 percent last season) while his walk rate has increased by nearly two percent.

Neither his BABIP (.186) nor LOB% (85 percent) is sustainable, either. There are too many red flags that pop up when we dig deeper.

Verdict: Parker could continue to pitch well, but he's easily the biggest regression candidate of the three pitchers in this article. I don't trust that he's that much better this season when all of his underlying numbers suggest he's probably still going to be a fairly average pitcher. I view him as a streamer at best, and he's not someone I would break the bank for with FAAB, as I don't see him maintaining anything close to this level of performance.

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