2010 Draft Prep: AL tiers using ERA and K/9
Over the past few weeks, I have been touting RC/27 as a metric that can make your drafting and roster management more efficient. With a single measure, you can size up the offensive potential of any position player in Fantasy.
Pitchers don't make our lives nearly so simple.
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Evaluating them by their projected Fantasy value (e.g., 5x5 value, Fantasy Points) can be a good way to set your initial draft rankings, but if you play in a non-standard format or just want to highlight a few sleepers who could exceed their playing time projection, you may want another method. The problem with settling on a single pitching stat for ranking purposes is that each measure has its blind spots and shortcomings. ERA tells us nothing (at least directly) about strikeouts. WHIP ignores home runs. Wins can be a product of run support and luck, and so it goes.
If one stat just won't do, then how about sorting pitchers by two stats? If you are tempted to cluster pitchers by ERA and WHIP, then you should probably try another approach. The problem is that these measures also correlate with each other. Looking at pitchers who started at least 20 games last season, 75 percent of the variation in ERA could be explained by the variation in WHIP. You won't find too many starting pitchers whose WHIP ranking is going to stray too far from their ERA ranking.
Would we find the same sort of redundancy if we grouped by pitchers by ERA and strikeout rates? Not so much. Variation in strikeouts per nine innings (K/9) explained only 14 percent of the variation in last year's ERAs. This is a fairly strong relationship, but there are enough holes in it that you can find patterns like the one in the table below.
Clearly, A.J. Burnett's value was not the same as the finesse pitchers listed in the table, but a simple sort by these 2009 ERA and WHIP data would suggest that it was. Because he stranded a lot of baserunners, Burnett didn't have the Fantasy value of a typical 4.04 ERA, 1.40 WHIP starting pitcher. There are many different ways that one can arrive at a particular ERA or WHIP, but Burnett's way -- missing bats, throwing wild and working out of jams -- has more value in Fantasy than contact pitching.
Using ERA and K/9 as ranking criteria is an effective way to sort out the Burnetts from the Nick Blackburns, as well as from pitchers like Jon Lester, who offer high strikeout rates without the wildness. Because we are working with two measures, a simple ranking is hard to achieve, at least at the outset. Fortunately, the pitchers form some clusters when we plot their projected ERAs and K/9 ratios. And plotting their projected stats is exactly what we have done for 70 American League starting pitchers who project to pitch at least 100 innings in 2010.
Each of the color-coded clusters represents a tier bounded by the pitchers' projected ERA and K/9 values. These tiers not only group pitchers with others who will have similar value, but they also place Blackburn and Lester in different categories from Burnett, despite the statistical similarities they share with him.
The ERA and WHIP thresholds for the tiers are as follows.
- Tier 1: ERA no higher than 3.60 and K/9 no lower than 7.5
- Tier 2: ERA no higher than 4.00 and K/9 no lower than 6.5
- Tier 3: ERA no higher than 4.40 and K/9 no lower than 6.0
- Tier 4: ERA no higher than 4.60 and K/9 no lower than 4.0
We will take a look at each of these clusters, finding the commonalities and shedding some light on some of the pitchers who don't fit neatly into their tiers.
Tier 1: The Elite
These are the best pitchers that the American League has to offer from a skills perspective, and the most reliable of these -- Felix Hernandez, Zack Greinke, CC Sabathia, Jon Lester and Justin Verlander -- merit a first- or second-round pick in mixed leagues. The others are here because of their potential for great rate stats, but they have durability issues (or in Joba Chamberlain's case, role uncertainty) that merit a downgrade.
Notable outliers: Sabathia is relatively light on Ks for this group, but he makes up for the slight deficit with outstanding control. He has not walked as many as three batters per nine innings since 2004, which is why he is consistently good for a sub-3.50 ERA and sub-1.20 WHIP. During his rookie season, Joba Chamberlain showed that he has the stuff to possibly be an elite pitcher, but last year he failed to replicate his high strikeout rate as a starter. He will need to do that in 2010, and of course, actually nail down a rotation spot first.
Tier 2: Solid Mixed Leaguers
Several of the pitchers in this group are practically a lock to be among the 20 best starters in the American League, and a few are just a cut below the elite (e.g., Josh Beckett, Cliff Lee, Jered Weaver). Others -- such as Brandon Morrow, Justin Masterson and Max Scherzer -- have a chance to be in the Top 20, but they will have to make good on their untapped potential. Ben Sheets and Daisuke Matsuzaka have the skill profile to hang with this group, but both will have to rebound from injuries.
Notable outliers: To look at James Shields' location on the graph (3.97 projected ERA, 7.0 projected K/9), he appears to be just a hair away from the third tier. However, if you assume that he gets a deserved BABIP adjustment (from .313 in '09) and returns to his previously sparkling walk rates, you have a projection that looks a tad pessimistic. Gavin Floyd, on the other hand, has to prove that he won't regress towards his previously-lackluster strikeout rates. Otherwise, it's back to the third tier for the 27 year-old.
Tier 3: Lower-End Mixed Leaguers
This group is largely divided between high-strikeout pitchers with less-than-stellar control and moderate-strikeout pitchers with above-average control. In other words, each of these pitchers is strong enough in at least one aspect of their game that they merit a mixed league slot, but weak enough in another that they don't belong in the elite or sub-elite tiers. Clay Buchholz and Marc Rzepczynski are close enough to the second tier and young enough that they could take a larger leap than anticipated. If you are comfortable with taking a chance on unproven pitchers with uncertain roles, then both hurlers could pay off big in the mid-to-late rounds of a mixed league draft.Notable outliers: A 4.19 ERA projection for Javier Vazquez might seem harsh, given his high K-rates and superb 2009 season. Just remember two things: '09 looked like a peak year for the 33 year-old Vazquez, and the Yankees' acquisition has struggled in home run parks (i.e., Chase Field, U.S. Cellular Field) before. Neftali Feliz has second-tier potential in 2010, but he will need better control than what he showed in the high minors.
Tier 4: The Rest
With a handful of exceptions, this group consists of low-strikeout pitchers who will be of minimal use in mixed leagues, but are sufficiently effective at minimizing walks and preventing homers to be valuable in AL-only leagues. As for the exceptions, you won't find a much riskier bunch to take a flier on. Ervin Santana, Dontrelle Willis, Carl Pavano and Ian Snell have all had their moments of Fantasy glory, but none posted an ERA below 4.80 in 2009. Colby Lewis did have a splendid season last year, but that was in Japan. He hasn't faced major league hitters since 2007.Notable outliers: When you strike out as few batters as Mark Buehrle does, you had better be extremely careful with walks and homers. He is not notably flyball-shy, but Buehrle's control is consistently impeccable. He is a rarity: a below-average strikeout pitcher you can absolutely trust in a mixed league.
Next up: National League Starting Pitchers by ERA and K/9 tiers.
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| Runs Created per 27 Outs (RC/27) -- An estimate of how many runs a lineup would produce per 27 outs if a particular player occupied each spot in the order; ex. the RC/27 for Miguel Cabrera would predict the productivity of a lineup where Cabrera (or his statistical equal) batted in all nine spots; created by Bill James Component ERA (ERC) -- An estimate of a what a pitcher's ERA would be if it were based solely on actual pitching performance; created by Bill James GO/AO -- Ground out-fly out ratio GB/FB -- Ground ball-fly ball ratio Batting Average per Balls in Play (BABIP) -- The percentage of balls in play (at bats minus strikeouts and home runs) that are base hits; research by Voros McCracken and others has established that this rate is largely random and has a norm of approximately 30% Isolated Power -- The difference between slugging percentage and batting average; created by Branch Rickey and Allan Roth Walk Rate -- Walks / (at bats + walks) Whiff Rate -- Strikeouts / at bats |
Al Melchior will be providing data-centric advice columns Fantasy owners all season. Click here to send him a question. Please put "Melchior" in the subject field.
