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SIERA Studs and Duds for Week 6

Welcome back to RotoBaller’s pitchers advanced stats and StatCast studs and duds article series! Each week we will select an advanced stat, choose two studs and two duds, and analyze what those stats could mean for future fantasy output. The next stat we will use is one that has been highly useful in terms of measuring pitcher’s independent performance, skill-interactive earned run average, or SIERA.

SIERA quantifies a pitcher's performance by trying to eliminate factors the pitcher can't control on their own. FIP is a stat that also attempts to do this, but unlike FIP, SIERA considers balls in play and adjusts for the type of ball in play. The formula can be found here for those who want to get into the nitty gritty.

SIERA is a better indicator of a pitcher's performance than ERA or FIP and can help predict future success or failure compared to a pitcher’s current ERA. This will be a great way to identify potential buy-low and sell-high candidates, so let’s get going!

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SIERA Studs 

All stats current as of 5/6/19 and courtesy of


Noah Syndergaard, New York Mets

(2-3, 5.02 ERA, 1.28 WHIP, 3.49 SIERA)

The Mets have had an exciting pitching staff for several seasons now, especially from a fantasy standpoint. However, several of their studs have underperformed to this point. One of those pitchers is Noah Syndergaard. Thor’s numbers have been anything but all-powerful and fantasy owners are likely panicked over his 5.02 ERA through 43 innings pitched. However, those owners may feel better after checking out his SIERA.

Syndergaard’s 3.49 SIERA suggests that he has been pitching much better than his ERA suggests. If this is the case, then why is his ERA so high? There are several possible explanations/contributing factors. They can all boil down to bad luck, but let’s look at the specifics. First, Syndergaard has maintained a strong 6.6-degree launch angle and 85.3-MPH exit velocity throughout the season. Despite this, his BABIP (batting average on balls in play) sits at a career-high .345 compared to his career average of .317. This means that more hits are falling against Syndergaard than they normally would. Further, his strand rate of 61.2% is much lower than his career mark of 74%, which could be hurting his ERA.

Turning to Syndergaard’s batted-ball profile, his batting average against is significantly higher than his expected batting average on all five of his pitches. These negative results are occurring despite generating favorable contact (6.6-degree launch angle, 85.3 average exit velocity, 27.1% hard-hit rate).

In sum, Syndergaard has pitched well this season but has gotten unlucky results. His stats under the hood point to him being the same Thor he’s always been, and, given time, the results should catch up. Fantasy owners may not be in full panic, but it certainly wouldn’t hurt to make a buy-low offer on Syndergaard before his numbers start to reflect his skill.


Hyun-Jin Ryu, Los Angeles Dodgers

(3-1, 2.55 ERA, 0.91 WHIP, 2.82 SIERA)

Our second SIERA stud has been a solid fantasy option since 2017 but is often overlooked. The Dodgers’ pitching rotation and bullpen have been finicky over the past several seasons but Hyun-Jin Ryu has pitched well whenever given the opportunity. This season has been no exception, as Ryu has posted a stellar 2.55 ERA with a 29.3% strikeout rate through 35 ⅓ IP and a 2.82 SIERA to back it up. If you couldn’t guess already, I feel that Ryu is legit. Let’s take a further look as to how he has found success.

Ryu stays out of trouble by limiting hard line drives/fly balls (average exit velocity 87.7 MPH, 38% hard-hit rate, 8.5-degree launch angle). These results can be attributed to his solid command; he hits his spots, and his 0.91 WHIP and miniscule 1.5% walk rate reflect that. This is important because Ryu does not throw all that hard (fastball average velocity of 90.4 MPH). He is still able to generate strikeouts without a blazing fastball because he mixes his fastball, cutter, sinker, changeup, and curveball effectively. In fact, Ryu currently has a career-high 12% swinging-strike rate.

Ryu is not a flashy fantasy option but he provides a high floor and is quite consistent. His SIERA supports his strong start to the season and he should be considered a solid number-three starter. The only worry is that he gets enough innings on a Dodgers team that is not afraid to shake things up, but with the number of injuries their pitching staff experiences, Ryu should be fine as long as he stays healthy and continues to pitch well.



All stats current as of 5/6/19 and courtesy of


Brad Keller, Kansas City Royals

(2-3, 3.99 ERA, 1.39 WHIP, 5.46 SIERA)

Our first SIERA dud came out of nowhere last season as a high-floor, effective fantasy starter. Brad Keller profiled as a pitch-to-contact groundball pitcher and did a very effective job, posting a 3.08 ERA in 140 ⅓ innings pitched. This season has not been as successful and while Keller’s ERA isn’t terrible, his SIERA suggests that he has been much worse. What is behind his ERA-SIERA discrepancy and what can it mean for his future performance?

Several things stick out as to why his SIERA is so high. The first is his lack of command. Keller did a better job throwing the baseball where he wanted it last season (8.6% walk rate, 1.30 WHIP). This season he has failed to do so; both metrics are higher, and his walk rate of 13.6% is startlingly higher. While these stats may not translate into runs in small samples, SIERA acknowledges that these type of numbers will not prove to be successful in the long run.

The other main sore point is the type of contact Keller has given up. As a groundball pitcher, getting hit hard is not all that worrisome so long as the ball is hit on the ground. He was able to make this happen last season, allowing an average exit velocity of 87.5 MPH with a 6.7-degree launch angle. However, he has not been able to replicate his success in 2019. Keller’s exit velocity has increased all the way to 90.9 MPH and his launch angle has bumped up to 9 degrees. This change in contact profile has led to an increase in expected batting average, slugging percentage, and on-base percentage, which are all things to avoid as a pitcher.

I considered Keller to be a sneaky late-round pick coming into 2019, but so far he has not impressed. A groundball pitcher cannot get away with a lack of command, as he has a smaller margin for error than a pitcher with a more robust pitch arsenal. The fact that Keller pitches a considerable portion of his games against the weak AL Central teams gives him an advantage, but I am worried about his fantasy value rest of season given his SIERA.


Aaron Sanchez, Toronto Blue Jays

(3-2, 3.09 ERA, 1.49 WHIP, 5.52 SIERA)

Our second SIERA dud was a breakout in 2016 but has battled injuries since. Aaron Sanchez was an intriguing fantasy option at one point due to his great sinker/changeup combo and a quick look at his stats seems to suggest that he is finally back and pitching well. However, he has a massive gap between his ERA and SIERA in the wrong direction, so should fantasy players be buying into his success?

Like Keller, Sanchez’s pitching style is more to contact and less for strikeouts. Also like Keller, Sanchez has several underlying stats that don’t jive with his stellar 3.09 ERA. First, Sanchez has an awful WHIP at 1.49 and a poor 14.3% walk rate. A pitcher who looks for contact cannot get away with putting this many runners on base for free without eventually getting burned.

Further, Sanchez has done a poor job locating his pitches. His fastball and sinker have been left up in the zone and in the middle of the plate too often. And while he does have some velocity on each at around 94 MPH, this type of location is not a recipe for success if Sanchez is to rely on ground balls for outs. What’s more, he is getting hit hard (career high 90.4 average exit velocity, 46% hard-hit rate). His hard-hit rate, coupled with his pitch location, has negatively affected his chances of giving up damaging hits, as his expected slugging percentage is a whopping .483 compared to a league average of .408.

Sanchez has gotten lucky to this point, but it seems like only a matter of time before his faults catch up to him. I would try to sell high on Sanchez while his peripherals still look enticing.

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