Four Lesser Owned Surprise Starting Pitchers Among SIERA Top 40

With nearly two and a half months left in the season, it’s time to either protect your pitching ratios if you’re at or near the top of the categories, or aggressively speculate on arms to hopefully gain additional points by the end of the season. One way to identify names to speculate on is by reducing the innings pitched minimum and checking out the SIERA leaderboard. That way you’ll get more recently recalled names in there too and although the sample size may be smaller, the wider search at least surfaces such names to further evaluate.

So let’s review four names you might be surprised to find among the top 40 SIERA with at least 20 innings pitched as a starter. Surprisingly, none of them are owned in more than 44% of CBS leagues.

Brandon Walter | 2.93 SIERA | CBS 34% Owned

Sometimes it’s obvious that most fantasy owners are looking solely at ERA when making roster decisions, as you’ll see in some of the following names. That isn’t the case with Walter though as he currently owns a 3.66 ERA. So not only have his skills been strong, driving that elite SIERA, but he’s also been a positive contributor in the majority of fantasy leagues already. In other words, we aren’t hoping his ERA eventually improves to meet the skills, his results have already been excellent. Aside from that ERA, his WHIP sits at just 0.96! I’ll get into whether I would personally pick him up in a shallower league, but regardless of my thoughts, it’s quite shocking that his ownership is so low.

Walter is not a top prospect. Heck, he isn’t even a prospect at all, top or not. He’s already 28 years old and didn’t even pitch at all last year because of a rotator cuff injury. So far this season, he has posted an above average strikeout rate with a low double digit SwStk%, despite featuring a fastball that averages just 91.9 MPH. He clearly knows the underwhelming fastball is problematic, so he’s been a kitchen sink guy, throwing five different pitches, all at least 12.8% of the time. According to PitchingBot, his changeup and cutter have both been above average, while Stuff+ thinks it’s been his sinker and slider. Between the two models, all his non-fastballs are above average pitches! Overall, though, both models agree he owns slightly below average stuff.

It’s been his command (botCmd of 52) and location (Location+ of 108) that have seemingly been behind his surprising success. He has walked a microscopic 1.6% of opposing batters, which is just unheard of. Of course, the sample size isn’t exactly large, but still, it’s been 46.2 innings now and he’s walked just three batters. His walk rate has been typically been strong in the minors, but not anywhere near this low, so I don’t think anyone saw this coming.

As for the rest of the season, remember that SIERA is accounting for his actual walk rate when making its calculation and doesn’t know or care whether that actual walk rate is sustainable. It’s a backward looking metric and so it doesn’t mean he should be expected to post a sub-3.00 ERA moving forward. It would be very difficult for him to maintain a walk rate that low and given below average stuff, is questionable whether he’ll be able to continue striking out batters at the rate he has. Still, he probably won’t implode, but he’s more of a matchup/streaming play in shallow mixed leagues in my eyes. I would likely add him if he were available in my league, but also be nervous every time he started when in my active lineup.

Zebby Matthews | 3.32 SIERA | 44% Owned

Remember above how I talked about many fantasy owners only look at ERA when making pitcher transactions? Walter was surprisingly not an example, but Matthews is the perfect poster child. Who wants a guy with a 6.26 ERA over 23 innings?! Me, that’s who. Let me tell you why.

Unlike Walter, Matthews was a pretty good prospect. He had ranked fourth in the Twins system with some solid scouting grades, including a 60/70 slider. In the minors, he consistently posted high-20% to low-30% strikeout rates with low-to-mid double digit SwStk% marks, along with elite walk rates. It’s the type of statistical profile I’ll chase. That is assuming he wasn’t getting by on deception to offset a poor fastball, which didn’t seem to be the case here. In our last writeup, we had Matthews sitting 94-97 with his fastball, topping out at 98 MPH. That sounds plenty good to me!

Then something happened this year, as we heard during spring training that his velocity had spiked. You know I’m a sucker for velocity surges, but many times those gains aren’t actually held when the regular season starts. For Matthews, it has. At Triple-A last year, he averaged 95.6 MPH with his fastball, but that dipped to 94.9 MPH during his MLB debut. This year, he has averaged 96.6 MPH with his fastball at Triple-A and 96.5 MPH with the Twins, for about a one mile per hour gain versus last year’s Triple-A mark and about a 1.6 MPH increase versus his time with the Twins. He already had an exciting profile, so I became even more interested thanks to the velocity gain.

Unfortunately, he dealt with some injury issues during spring training and was ultimately sent to Triple-A, failing to make the opening day rotation. He was finally recalled in mid-may, making four starts before hitting the IL with a strained right shoulder. He’s back now, and the good news is that his velocity was actually the highest of the season in his first start after returning from the IL, so it seems like his shoulder is a non-issue. Remember the scouting write-up on his velocity? He’s no longer merely sitting 94-97, as he actually just averaged 96.9 MPH in that last start!

Matthews throws four pitches, though he’s mostly four-seamer, slider, cutter. His fastball has gained points in both PitchingBot and Stuff+ compared to last year, likely thanks to the increased velocity and is now clearly an above average pitch. His slider has also gained significantly and is now a fantastic pitch according to the models. His cutter is not, though, so he’s essentially using two strong pitches right now. His four-seamer has generated an above average 9.7% SwStk%, while his slider has been elite with a 22.3% mark. His cutter and changeup have been meh, but the curveball has been real good, but only thrown 5.5% of the time.

What’s killing Mathews’ ERA right now is a super inflated .410 BABIP, which has conspired against his LOB%, driving it down to just 64%. Yes, his 25.4% LD% allowed definitely plays a role in the high BABIP, which also explains why his 4.01 xERA is much higher than his 3.32 SIERA. But LD% over a small sample size is mostly meaningless and it doesn’t mean it’ll remain at that elevated level. All I care about is the near 30% strikeout rate, 13.8% SwStk% and 30.3% CSW%. His walk rate is at a professional high, but given his history, I would expect improvement. I own him in all three of my leagues and he’s nearly an automatic every week start.

Eric Lauer 라우어 | 3.44 SIERA | 40% Owned

Seriously, whaaaaat?! Lauer last pitched in the Majors in 2023 when he posted a 6.56 ERA. He did record strong ERA marks back in 2021 and 2022, but his SIERA marks were above 4.00. This is the first time that Lauer has actually posted strong skills and a SIERA below 4.00.

The obvious metric that stands out is the 27.1% strikeout rate. He had never been above 23.9% previously. His fastball velocity is down from his last two large sample size seasons in 2021 and 2022 and his pitch mix hasn’t really been altered. That fastball is sitting at the worst mark of his career from both pitch models, but his cutter, his second most thrown pitch, has improved significantly, with Stuff+ now indicating it’s a slightly above average pitch. Overall though, the models agree his stuff is well below average and actually worse than his previous seasons.

If we look at his CSW%, it’s marginally above his career average, but lower than his 2022 mark. His SwStk% is right at his career average and below both 2021 and 2022 season marks. So I’m about to throw up my hands and give up, because I can’t explain how he has managed to post a 27.1% strikeout rate. A look at Baseball-Reference helps a bit here, as the strike rates they calculate are all a bit better than his career average. Still, I can’t imagine he maintained anywhere close to this strikeout rate over the rest of the season.

He’s an extreme fly ball pitcher, which means that fewer expected strikeouts result in more balls in play, resulting in more home runs. He has posted the lowest HR/FB rate of his career so far, along with excellent luck metrics, all of which should regress moving forward. His xERA of 3.06 actually suggests he’s deserving of suppressed BABIP and HR/FB rate marks, but that doesn’t mean that he’ll be able to continue limiting quality contact like this. I think I’d rather gamble on Walter.

Michael Soroka | 3.57 SIERA | 35% Owned

Now here’s a blast from the past! Back in 2019, Soroka was the Braves’ third best prospect and ranked 36th overall. That year, he posted a 2.68 ERA, driven by a groundball tilt and excellent control (and some good fortune). Since, he’s dealt with a plethora of injuries and has barely pitched. Fast forward to 2025 and he’s a completely new pitcher.

Like Matthews, we heard about Soroka’s velocity being up during spring training. It quickly made him a trendy sleeper as he was suddenly getting drafted in league sizes you would never expect someone with his recent history to be drafted in. That velocity spike hasn’t totally held, though he’s still averaging the best mark of his career, but just not as high as the 94.7 MPH he averaged during spring training. He is also throwing that fastball at a career high clip, by far, mostly at the expense of his sinker. He has also scrapped his slider in favor of a curveball, which has been his most thrown secondary.

With the added velocity, PitchingBot thinks the fastball is an above average pitch, though interestingly Stuff+ thinks it’s well below average. The pitch’s SwStk% is around the league average and marginally higher than his career average, so it’s difficult to decide which model to believe. The models also disagree on his new curveball, which PitchingBot thinks is below average this time, while Stuff+ thinks is exactly average. Overall, both models calculate below average stuff, even with the increased velocity, and certainly not better than his historical marks.

That surprises me given the career best strikeout rate and CSW%, though his SwStk% is actually just below his career average and below the league average. Aside from changes to his repertoire, he’s no longer a groundball pitcher, now generating them at around a league average clip.

What has happened to Soroka’s ERA is a 65.8% LOB%, which is surprising given the better than league average BABIP and only slightly elevated HR/FB rate. That BABIP looks legit and his xERA is even lower than his SIERA thanks to a stupendous 14.4% LD%. As a result, his ERA really, truly should be somewhere in the mid-3.00 range right now.

But don’t necessarily rush out to grab him! His SwStk% is still below average, making me think he might not be able to sustain a mid-20% strikeout rate, particularly given the below average stuff, and we can’t possibly expect such a suppressed LD% continuing. I definitely think he’ll post better results over the rest of the season, but I also definitely think those results won’t come close to his current SIERA or xERA because I don’t think the underlying skills driving those calculations will be maintained. He should produce positive value in deeper mixed and NL-Only leagues soon though, but I’m not interested in shallow formats.