Starting Pitchers Who Have Been Outperforming Their SIERA

Two of the best predictors of future pitcher success – K-BB% and SIERA – tend to correlate well with each other. So when you see a pitcher outperforming their SIERA while posting a low K-BB%, you have good reason to expect regression.

The visual below shows pitchers with 50 innings sorted by the largest difference in their ERA minus SIERA.

We have some starting pitchers on this list who are outperforming their SIERA but have a strong K-BB%, which typically indicates they’re succeeding by skill and luck. That’s how breakouts occur: when a pitcher’s skills align with their luck factors or some combination of that formula.

On this list, those pitchers are outliers. Shohei Ohtani, Ben Brown, Zack Wheeler, Cam Schlittler, Payton Tolle, Max Meyer, and Sonny Gray have strong K-BB% numbers so, while there could be regression toward their SIERA, they have strong skills to give us more confidence in their outcomes.

Meanwhile, several pitchers on this list have a K-BB% in the single digits or hovering around 10-11%, which are concerning levels. We’ll examine a few starting pitchers that have been outperforming their SIERAs, and whether we should buy, sell, or hold for fantasy baseball purposes.

Eduardo Rodriguez, SP, Diamondbacks

When most of a pitcher’s ERA estimators hover 2.00 higher than their actual ERA, there’s a good chance we’re dealing with a risky profile. That’s the case with Eduardo Rodriguez. He has been fortunate, with a .251 BABIP and a 86.9% strand rate helping suppress his 2.27 ERA. For context, Rodriguez’s BABIP is around 50 points lower with a strand rate that’s 12 percentage points higher than his career average.

Besides those factors, Rodriguez’s 8.2% K-BB% would be the lowest mark of his career. His K-BB% was 12.1% over the past two seasons, already notably below his career average (14.6%). That aligns with Rodriguez’s lowly 7.9% swinging-strike rate this year, over two points below his career norm (10.2%). 

Rodriguez lacks above-average stuff, surviving as a command artist. None of Rodriguez’s pitches has an above-average stuff grade, though four of his five pitches have a Location+ at 105 or above. His 107 Location+ is five points above his career average. Pitchers with high-end command can outpitch their peripherals and underlying metrics, which seems to be the case with him this year. 

Interestingly, Rodriguez’s changeup Location+ jumped to 111 after being at 102 (2025) and 105 (2024). That’s notable because Rodriguez was peppering his changeup low and away from right-handed hitters. The change lived in that bottom right corner, away from righties. However, Rodriguez’s changeup is catching more of the zone, with a 40.8% zone rate (2026). That’s up seven points compared to the changeup zone rates in 2025 (33.8%) and 2024 (32.3%). 

Meanwhile, Rodriguez’s four-seamer has improved from a command standpoint. Rodriguez’s 109 Location+ via the four-seamer is five points higher than his career average. The heatmaps seem to look more favorable for the Location+ grades, though the heater has only been thrown one inch higher to righties and one inch closer to the middle of the plate to lefties. 

In the age of stuff, velocity, and whiffs, Rodriguez continues to defy the odds with his command-focused profile. Ride the wave if you roster Rodriguez, but understand that regression will hit. 

Monday Update: Rodriguez threw a quality start, with five hits, one earned run, zero walks, and one strikeout across seven innings against the Giants. He was fortunate with 12 batted balls hit hard (over 95 mph) while he generated a 12.1% swinging-strike rate. These are the types of outings in favorable matchups that keep us interested.

Walbert Ureña, SP, Angels

I wrote about Walbert Ureña in May when covering relievers turned into starting pitchers. Looking back, I was intrigued, but understood that the data looked more concerning than favorable for him. Control has been the biggest issue for Ureña, with a 39.4% ball rate and a decent 11.4% swinging-strike rate. That led to a 10.2% K-BB%, which coincides with his 4.40 SIERA.

Since he generates plenty of groundballs (54.5%), his 3.25 xERA is the most optimistic among the ERA estimators, as they account for contact quality. Specifically, Ureña’s sinker leads his arsenal by inducing a 62% groundball rate with the changeup (54.7%) close behind. Though Ureña’s sinker generates groundballs, right-handed hitters (.399 wOBA, .353 xwOBA) and left-handed hitters (.404 wOBA, .381 xwOBA) hit them hard. 

However, Ureña’s changeup generates weak contact against righties (.246 wOBA, .187 xwOBA) and lefties (.262 wOBA, .248 xwOBA) while eliciting whiffs (17% swinging-strike rate). As we discussed in the previous article about Ureña, his sinker and changeup have similar induced movement profiles, which potentially means they tunnel well off each other. 

Ureña’s sinker remains one of his best pitches from a Stuff+ (111) standpoint, while he commands the changeup well (117 Location+). The wild card might be Ureña’s sweeper slider with a 120 Stuff+, 11% swinging-strike rate, and a weak contact machine against righties (.139 wOBA, .229 xwOBA).

Interestingly, Ureña has slightly above-average Stuff+ (101) and Location+ (103), suggesting we may want to trust the results more than the expected metrics. Since SIERA correlates well with K-BB%, it makes sense for Ureña to have a poor SIERA. However, Ureña’s xERA gives us an idea of the type of pitch he could be if he continues to induce weak contact. 

Control will be a challenge for Ureña, but there’s a chance for the whiffs to improve. Hold and be patient with Ureña if he hits some bumps in the road. He continues to be a streaming starting pitcher that might have a short stay on our rosters, depending on the format. 

Justin Wrobleski, SP, Dodgers

Among the Dodgers’ starting pitchers, Justin Wrobleski trails only Shohei Ohtani and Yoshinobu Yamamoto in ERA. All of the ERA estimators and advanced metrics, however, tell us there’s a low probability for Wrobleski to keep up his successful season. Unlike Ureña, Wrobleski’s xERA doesn’t inspire confidence. Among qualified pitchers, Wrobleski has the 8th-best walk rate with the 62nd-highest strikeout rate out of 65 players. That tells us Wrobleski controls the zone but lacks the whiffs. 

Wrobleski is a command artist. That’s been evident with Wrobleski’s 111 Location+ this season after a 110 Location+ last year. Among his six pitches thrown, five of Wrobleski’s pitches have average to above-average Location+ grades, with three above 105. That includes Wrobleski’s four-seam (118), sinker (109), and curveball (113) in Location+. 

Wrobleski had mediocre Stuff+ grades last year (101). That has fallen to 95 this year with his four-seam (92), slider (104), and changeup (92) dropping the most from last season. Wrobleski’s four-seamer has a nearly identical movement profile so the Stuff+ grade might be fluky. He has been throwing a slower changeup (down more than 1 mph), that has lost nearly four inches of drop while adding over two inches of arm-side fade. However, Wrobleski hardly throws his changeup, tossing them 5.7% of the time to right-handed hitters and almost never to lefties. It’s a noisy small sample with the changeup. 

If we use Wrobleski’s 3.63 FIP as the ceiling outcome, fantasy managers would probably accept that. Since Wrobleski tends to command several pitches well, it’s understandable that he could outpitch his K-BB% and low swinging-strike rate (8%). Most fantasy managers aren’t expecting Wrobleski to continue pitching this well, so it’s best to hold and ride the wave if you roster him. 

Brandon Young, SP, Orioles

Brandon Young has been pitching well in June, with a 2.76 ERA, 1.19 WHIP, and an 11.5% K-BB%. With Young’s overall 9.6% K-BB%, his ERA estimators don’t look favorable. Young posted a career high in whiffs (23) on June 27, with a previous high of 12. That tells us the whiffs might be rare, but there’s potential for them within Young’s profile. 

The newest change in Young’s arsenal involves him throwing a slower splitter over the past two months. Young threw his splitter at 87.4 mph in April, 85.5 mph in May, and down to 83.2 mph in June. That coincides with two additional inches of drop each month with the lower velocity. 

Specifically, Young’s splitter is dropping 37 inches in June with 3-4 fewer inches of arm side fade (7.1 inches) compared to April. Besides Young’s splitter movement profile changes recently, the locations have moved more toward his arm-side. In the heatmaps below, we can see Young’s splitter thrown lower and below the zone toward the middle of the plate in April, which shifted more toward his arm side in May and June. 

The splitter movement and location changes intrigue us, and those inputs have translated into positive results. Young’s splitter is eliciting a 15.2% swinging-strike rate and allowing a .145 wOBA (.233 xwOBA) in June. For context, Young’s splitter had a 7.1% swinging-strike rate and allowed a .401 wOBA (.392 xwOBA) in April and May. 

From a command standpoint, Young’s four-seamer (105), sinker (106), and curveball (104) lead his arsenal in Location+. The four-seamer has unique traits with nearly 18 inches (17.9) of induced vertical break, which he peppers across the top part of the zone. Young has been throwing fewer four-seamers (31.3%) to right-handed hitters, down nearly six points. Meanwhile, Young’s four-seamer continues to generate weak contact (.228 wOBA, .300 xwOBA). 

He relies heavily on the four-seamer against left-handed hitters (46.6%). The overall results have been better this season .291 wOBA, though the .342 xwOBA is similar to last season. Young tends to command most of his pitches well, but the wild card is his slider from a stuff standpoint. His slider boasts a 107 Stuff+ and a 22.2% swinging-strike rate. 

Young leans on his slider (32%), four-seamer (31.3%), and sinker (25.9%) over 89% of the time against right-handed hitters. The slider generates weak contact (.241 wOBA, .236 xwOBA) and a 22% swinging-strike rate against righties. It’s a gyro-like slider that doesn’t stand out from a movement profile perspective, but we like to see him continue throwing them more to righties (up 11 percentage points) this season. 

As long as we’re valuing Young as a streamer, we should continue holding him on our fantasy rosters. Though the expected ERA metrics suggest regression based on Young’s skills, there are a few pitches to like (splitter, slider, and four-seam) that could help him evolve to generate more strikeouts.