SIERA

We last covered the pitching version of BABIP to explore how you can quantify the pitcher’s luck as a way to evaluate his talent and the legitimacy of his production. Today, we’ll spend some time breaking down a sabermetric stat called SIERA, one of my favorite go-to pitching sabermetrics to look into, so let’s get into it.

The Stat

SIERA stands for Skill Interactive ERA, and is in the ERA, FIP, and xFIP family. When you see the stat, it’s in the same format as ERA, so it should be easy to look at and understand. Similar to FIP and xFIP, the goal of SIERA is to figure out what the true skill of the pitcher is, and how they should be doing based on what they are doing.

Involved in the SIERA calculations are strikeout rate, walk rate, and ground ball rate – all relatively within a pitcher’s control, and usually a point of consistency for pitchers from year to year. These are things you want in an ERA predictor because you want to measure what a pitcher has control of in order to measure his skill. What SIERA does that stats like FIP and xFIP don’t do is that it factors in the type of ball that gets put into play and adjusts for that result. To help make sense of that, if a pitcher has a high xFIP, but has also induced a high proportion of grounders and pop-ups instead of line drives, his SIERA will be lower than his xFIP because he is being rewarded by SIERA for the grounders and fly balls he is inducing.

All that being said, if SIERA still seems confusing, here’s an easier way to think about it… High strikeouts, low walks, and ground balls all result in a low SIERA, and point to a pitcher who is doing what is in his power to reveal his true talent.

Why Is This Stat Important?

SIERA reveals just how important it is for pitchers to get strikeouts and gives value to pitchers who may not get a ton of strikeouts but can still induce ground balls, which can result in outs and double plays. SIERA factors in the ability of pitchers to induce ground balls and fly balls to get outs more than FIP or xFIP.

The top 12 in SIERA from 2019 all had 10.5 K/9 or more, and not a name should be surprising – Cole, Scherzer, Verlander, deGrom, Bieber, Strasburg, Buehler, Morton, Giolito, Darvish, Boyd, and Flaherty all appear.

The top 9 players aren’t that surprising to see, nor is Flaherty – high strikeout pitchers that you likely drafted pretty early. The names I like that offer some value are Yu Darvish and Matthew Boyd. Boyd’s ERA was nearly a point higher than his SIERA, suggesting that his true talent is that of a high strikeout, mid-3 ERA pitcher like Giolito, Lance Lynn, or even Aaron Nola. Understanding SIERA can help you find value in players that you may think are much worse than they actually are, and that is only because ERA is not good enough.

Something that I’ve established in the last few podcast episodes, and something that is understood now by many baseball analysts is that ERA doesn’t consider luck, park factors, and fielding and isn’t the best barometer at how a pitcher is truly doing because there are so many things out of a pitcher’s control that don’t get factored in to ERA. With SIERA, all of those things are considered, and so it’s a much better measurement of how the pitcher himself is doing.

FIP does not take balls in play into account, therefore it is limited as an evaluation tool. It can paint you some of the picture, but not the whole thing.

According to the website Fansided, “SIERA is the most in-depth ERA-estimator you are going to find, and it is also the most accurate. It performs better than FIP and xFIP in predicting next year’s ERA and in year-to-year consistency.”

My final recommendation with SIERA is to continue monitoring pitchers’ SIERAs throughout the season, and like always, to look at it in conjunction with other stats. But if you are seeing discrepancies between FIP and SIERA, I’d lean towards the latter in my analysis.

How Do I Find This Stat?

This stat is on Fangraphs, so first, go there and up at the top right, you’ll select leaders and from the drop-down choose 2019. Once this season gets started, you’ll be looking at 2020 data.

Then, you’ll want to select Advanced from the toolbar you find when you scroll down a little bit. And once you’ve found that and selected advanced, you’ll want to click on SIERA, which is in the column all the way to the right and sort from low to high SIERA.

As I said before, a lot of those top guys are not surprising. So let’s look at a few players that have a discrepancy between their ERA and SIERA in either direction. One very large gap is in Hyun-Jin Ryu’s ERA to SIERA. He had an outstanding year last year, with an incredible 2.32 ERA. SIERA suggested he should have been closer to 3.77. This is why I never wanted Ryu last year and why I refused to draft him this year – I didn’t trust what his ERA was telling me. On the other hand, German Marquez had a bloated 4.76 ERA, but his SIERA (which takes into account the park factor of pitching in Colorado) suggests he should have pitched nearly a run better at 3.85.

Who Do I Target?

Finally – who should you target this year, based on SIERA? My suggestion is Robbie Ray, although with a caveat. Remember, SIERA rewards a low walk rate, a high strikeout rate, and a good ground ball rate. Robbie Ray had a horrible walk rate last year, averaging nearly 4.5 walks per 9 innings, and still managed a 4.02 SIERA vs a 4.34 ERA. This means he’s a better pitcher than his 4.34 ERA suggests. In the 3 years previous, he has had a sub 4 SIERA at 3.89, 3.53, and 3.59, with only the 3.53 SIERA being higher than his ERA that year. So the caveat with suggesting Robbie Ray, is watching the walk rate. If you see his walk rate spiking and his SIERA starts to spike, I would cut ties, even if his ERA looks good. In fact, that’s more reason to try trading him.

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I also wanted to spend some time today going over the impact of players opting out of the season, but rather than focusing on them, I want to focus on who will be impacted most by those decisions. So first, here are the major players that have opted out in 2020, and although the names might not be huge, the impact will be felt in fantasy baseball.

Ryan Zimmerman and Joe Ross from the Nationals, Ian Desmond from the Rockies, David Price from the Dodgers, and Nick Markakis from the Braves.

First, with Ryan Zimmerman opting out, you have a platoon spot opening up at first base. Zim would also have been a prime DH candidate. So who is going to benefit most from his absence? I think you’re likely to see more at-bats from Howie Kendrick at first and at DH, as well as Eric Thames. I also think there’s a chance for more at-bats for Asdrubal Cabrera as well, who had a decent year last year with the Nats in the second half.

Another National that opted out was Joe Ross, who likely would have been the fifth starter. Instead, you’re likely to see Eric Fedde and Austin Voth compete for time there. Watch them because one of them is going to emerge and be pretty good, the other will probably become a stretch arm in the bullpen, which could also turn out to be very valuable this year especially early on if pitchers aren’t able to go deep into games.

Former National and current Rockies outfielder Ian Desmond also will not be playing this year, and a crowded outfield just became a little bit clearer. Charlie Blackmon’s time in the outfield was never really in question, though they should DH him, since his defense is in decline. And if they do that, it would open the outfield even more. But, with just Desi sitting out, that means more time for David Dahl, Garrett Hampson, Sam Hilliard, and Raimel Tapia to see at bats.

David Price sitting out is going to create a domino effect in the Dodgers’ clubhouse. Buehler and Kershaw are definitely numbers 1 and 2 in the rotation. I think we are likely to see Alex Wood in the rotation. But the rest is very unclear. The Dodgers have Julio Urias, Dustin May, Ross Stripling, Brusdar Graterol, and Tony Gonsolin all who could see time starting. You could see a six man rotation in LA. You could see a rotation where some pitchers start for 3 innings, and another arm comes in for another 3 innings, before going to a set up man or a closer. My suggestion is to keep an eye on Urias, May, Stripling, Graterol, and Gonsolin in LA because you may find value with all of them.

Nick Markakis is also sitting out of this year. Likely the starting right fielder, Markakis’ absence opens a hole in the outfield and in the lineup. Acuna may end up moving to right for Ender Inciarte to play center full time, so that may give Inciarte some more at bats. What may end up happening is that there’s more playing time in left field for Marcell Ozuna and Austin Riley. You could see a platoon there or in center in some combination with Inciarte. I’d also keep an eye on prospect Christian Pache.

Well, that’s all for today. Next time, we’ll do an intro into statcast data and what that entails. Thanks for reading.