12/3/20
The latest episode of “The Sleeper and the Bust” is live. Support the show by subscribing to Fangraphs! With a standard $20 membership, you help maintain and improve our database of stats and graphs as well as our staff of 8 full-time employees and over 50 contributors. The premium ad-free membership at $50 year supports site growth and also includes faster load speeds and better site performance. You can also support monthly for just $3.
Follow us on Twitter
NOTABLE TRANSACTIONS/INJURIES/RUMORS
Read the rest of this entry »
Podcast: Play in new window | Download
Subscribe: Android | RSS
Yesterday, I listed and discussed the starting pitchers whose ERAs underperformed their SIERA marks by the most significant margins. I then reviewed the pitchers’ BABIP, LOB%, and HR/FB marks and identified which of the three metrics were driving the SIERA underperformance and what the chances for improvement in 2021 are. Let’s now shift over to the SIERA overperformers. Which of the three “luck” metrics drove such overperformance this season and can that last through next year? Let’s discuss the fantasy relevant names.
Back in 2018, I introduced a game theory approach for comparing baseball projection systems. Proudly, the article was nominated for Baseball Article of the Year by the Fantasy Sports Writers Association (FSWA). The game theory methodology is now back for its third straight year.
This approach is not the standard projections comparison analysis that most others embark on. The typical comparison makes use of some type of statistical measure. The standard analysis involves calculating least square errors, performing chi-squared tests, or perhaps even hypothesis testing. My method does not use any of these capable methods.
Of the three ERA estimators available on FanGraphs (SIERA, xFIP, FIP), SIERA is the best at predicting future ERA, even though it was designed as a backwards-looking metric, like the other two. If you’re still using xFIP or FIP in your pitcher analysis, then stop, and immediately switch to SIERA. In a short 60 game season, focusing on SIERA, rather than ERA, is even more important when forecasting a pitcher’s future performance.
The underlying skills that drive SIERA stabilize more quickly and the metric isn’t influenced by the gyrations of the three “luck metrics” — BABIP, LOB%, and HR/FB — which don’t have enough time to settle around the pitcher’s true talent level. ERA is heavily influenced by how a pitcher performs in those three metrics, but there’s far too much randomness involved to place significant weight on them, even over a full 162 game season. Remember though, even SIERA isn’t perfect because there are pitchers who consistently underperform or outperform due to some skill or lack thereof that has been a challenge to identify.
So let’s review the pitchers who underperformed their SIERA marks most this season (minimum 40 innings pitched). I’ll identify which of the three luck metrics fueled that underperformance and discuss whether there’s a chance the pitcher underperforms again in 2021 or reverts closer to his SIERA (I’ll only discuss the fantasy relevant names).
With drafts beginning to ramp up, it is important to monitor where players are being draft on a regular basis. Throughout draft season, I will be doing that work for you with regular updates on the Average Draft Position on NFBC up until Opening Day.
• Pitcher Kohei Arihara (NPB) will join shortstop Ha-Seong Kim (KBO) as the top international free agents.
The news on Kim has been known for a while but the Arihara news will be interesting for any team needing pitching (i.e. all teams). The 28-year-old Arihara had his best season in 2019 with a 2.46 ERA, 0.919 WHIP, and 8.8 K/9. All the stats were a little worse in 2020. The Davenport translation on his 2020 season is a 5.09 ERA and 5.9 K/9. Not the best numbers so maybe he’ll end up as a long reliever.
• The KBO’s Sung-Bum Na (OF/DH) has been posted and MLB teams have 30 days to negotiate a signing.
Na has been an above-average hitter in KBO since his second year in the league and a star-level performer for much of that time. In 4140 career plate appearances since debuting as a 23-year-old, he’s batted .317/.384/.542 with 179 home runs, 244 doubles and 25 triples. … He moved to right field for the 2015 campaign, and that’s been his primary defensive home since, although he’s still logged some occasional time in center — most recently in 2019 when he started 18 games there. However, Na’s 2019 season was cut short by a severe knee injury that resulted in him being placed on a stretcher and taken off the field in an ambulance, as he told ESPN’s Marly Rivera earlier this year. He underwent surgery and spent seven months rehabbing from that procedure.
Na has been an above-average hitter in KBO since his second year in the league and a star-level performer for much of that time. In 4140 career plate appearances since debuting as a 23-year-old, he’s batted .317/.384/.542 with 179 home runs, 244 doubles and 25 triples.
…
He moved to right field for the 2015 campaign, and that’s been his primary defensive home since, although he’s still logged some occasional time in center — most recently in 2019 when he started 18 games there. However, Na’s 2019 season was cut short by a severe knee injury that resulted in him being placed on a stretcher and taken off the field in an ambulance, as he told ESPN’s Marly Rivera earlier this year. He underwent surgery and spent seven months rehabbing from that procedure.
Na doesn’t seem like a priority add with the defensive limitations and he is coming off a major knee injury. Quite a few major leaguers fit the desciption as a broken down slugger. Read the rest of this entry »
12/1/20
Yesterday, I identified and discussed the hitters whose SwStk% marks improved the most versus 2019. Today, let’s check in on the opposite end of the list. Remember that “decliner” in this context actually means these hitters’ SwStk% marks have increased, so their skill declined, but the metric we’re using to evaluate their skill has risen.
Acquiring saves in fantasy baseball is becoming more and more of a headache. The Tampa Bay Rays had 12 different pitchers notch a save in 2020. Imagine if it was a season of normal length? With the league trending towards using their best pitchers in high leverage positions instead of the conventional only ninth-inning role, it seems like grabbing saves are only going to get more complicated. Below you will see some closers that likely won’t be too popular but could help you in the long run. A quick side note, there are a lot of free-agent relief pitchers (ie. Brad Hand) so things can definitely change.
If you would like to read parts one and two you can check them out here and here.