Attacking Offensive Categories with Z-Scores

July 18, 2020

Ariel Cohen uses his updated 2020 ATC projections to project leaders in offensive roto categories for fantasy baseball and employs Z-scores to find undervalued ADP draft targets.

The way to win at fantasy baseball is to generate the most aggregate value on your roster. One cannot win with just an average fantasy team; one must be better than the mean. To accomplish this, owners must spend their fantasy capital efficiently in acquiring talent. Finding and drafting undervalued players is the key. Of course, for rotisserie baseball, an added complexity is ensuring the categorical balance of scoring statistics.

For those of you who read my work often, you might know that I prefer auctions to snake drafts. However, the serpentine draft adds the element of a jigsaw puzzle – knowing how and when to fit all of your pieces into the frame. To make it even more difficult, in fantasy baseball everyone takes turns choosing pieces from the same box. That means another team may take a needed piece before it is your turn to draw from the lot. Planning ahead is the best way to attack the game.

Today, I will use the ATC Projections along with the current NFBC ADP to uncover undervalued players. But more than that, we will go through the landscape of each offensive category, and perhaps make a few observations along the way. Let’s find out when and where to take your specific puzzle pieces in 2020.

Setting the Stage

The two needed components of any undervalued/overvalued pricing analysis are:

• Projections
• Market

Regarding the former, I will use my own ATC Projections. Over the past few seasons, the ATC Projections have been accretive in uncovering value in fantasy auctions/drafts.

As for the “market,” I will use the current NFBC published ADP (Average Draft Position). The NFBC is the gold standard these days for ADP data with competitors wagering non-trivial amounts of money to play. I find that mock drafts are somewhat unreliable, especially early in the offseason. With the NFBC’s reliability, uniformity, robustness, and accessibility of data, they are currently the best source of available ADP. This year is particularly challenging for good draft data, but the NFBC is a fine source.

For this article’s draft value comparisons, I look at:

• The player ranks as computed by the ATC Projections run through my own auction value calculator (standard NFBC 15-team 5x5 roto league settings).
• The current NFBC ADP (of leagues from June 28, 2020 to July 10, 2020).

Ranks are calculated for offense only; we will leave pitching for another time. In the analysis below, I will list the ATC hitter rank, NFBC hitter rank, and overall ADP information.

In this article, I refer to z-scores (sometimes referred to as standard scores). Z-Scores are an excellent way to gauge how a player stacks up with the other above replacement level players per category. A z-score of zero is an average player. A +1 z-score means that the player is one standard deviation above average. A negative z-score indicates a below-average player for the category, etc. The distribution of z-scores against market pricing will let us know which categories require us to pay up somewhat, and which ones we should not.

Today, we will only look at undervalued players, defined as a player which ATC values more highly than the market. We will also ignore all players drafted in the first two rounds of the NFBC (an ADP of <= 30), as these players aren’t likely to be a large bargain anyways.

Batting Average

Looking for help in batting average? There are a number of excellent choices to help you later on in drafts. In fact, we can find a number of hotspots:

Rounds 13/14 – Alex Verdugo (.297), Jean Segura (.287), Bryan Reynolds (.285), Adam Eaton (.283), Lorenzo Cain (.278)

Rounds 17/18 – Luis Arraez (.311), Howie Kendrick (.305), Daniel Murphy (.288), Starlin Castro (.282)

A hotspot is a pocket of players close in ADP, all who are undervalued, and either play the same position, or are projected for similar statistics. The theory is that if you wanted to draft a specific player, say Jean Segura – you run the risk of another league player (who is in love with him) drafting him first! However, if you head into the hotspot (here, the 13^th/14^th rounds) with the mindset of obtaining any piece that fits – not any one specific player - you will be able to find at least one of your identified undervalued players still available for you to draft … and sometimes even a round later than expected!

Bryan Reynolds in the 13^th round is one of ATC’s most undervalued players this season. I have personally drafted him on a number of rosters this season. He batted .351 in the first half of 2019! In the second half, he batted a mere .285 … still amazing! To boot, he has also shown the ability to hit for modest power and modest speed.

Luis Arraez could be in contention for an AL batting title this season. He will hit in the currently stacked Twins lineup – and can be had in the 18^th round of 15-team drafts. If you need to catch up on batting average late in the game, Arraez is an excellent plug for that hole.

Home runs

Unlike batting average, undervalued premium power is NOT available late. Almost all of the players on the list above are being drafted no later than round 9. In fact, the 4^th - 7^th rounds represent 13 of the top 20 undervalued players.

With this in mind, plan to draft your power early on. Stock up on home runs. The fable that one can wait on power is not true; homerun totals are up in baseball on the whole.

We can find a few diamonds in the rough here, available in later rounds. Khris Davis, who was being drafted in 4^th / 5^th rounds in 2019, now finds himself going after pick 160. Davis was injured last year, but otherwise he is a perennial lock for 40 HR power. Although starting to age, Edwin Encarnacion has been reliable in past seasons for HR, and is available this year in the 11^th round.

Way down after pick 250 – Hunter Renfroe is an emergency power source. ATC is projecting 12 HR for him in the short season – at a 3+ round discount.

Stolen Bases

Outside of the first two rounds – most of the top bargain stolen base players can be found after round 10! There is no need to vastly overpay for steals.

Elvis Andrus has a projected Z-Score of +2.25. You can draft an undervalued player who will be two standard deviations above average – with your 11^th round pick!

Rounds 13-15 is a stolen base hotspot. Included in this group are Lorenzo Cain (7), Adam Eaton (5), Jean Segura (5), Rougned Odor (4) and Ryan Braun (3). Plan accordingly. Notably, Segura was also mentioned earlier with the batting average bargains.

Before I close out the discussion on stolen bases – notice that the 20^th player’s z-score on the list is A.J. Pollock at +0.12. Compared to BA (+0.76) and HR (+0.93) – that number is quite low, and close to the average Z-Score level of 0. This means that there indeed is a market premium for stolen bases. There are more overvalued speedsters than undervalued ones.

One should never go overboard on overpaying for players – but it would be wise to bank a player in the first few rounds to give you a large base of steals, even if you push him up a half-round or so. The z-Score spread confirms this.

Runs Scored

Of all offensive scoring categories, runs scored have historically been highly correlated with the overall winners of leagues. The fantasy teams that score the most runs - often win their fantasy baseball leagues. Do not simply “go for power and speed” - consciously put emphasis on the run production categories.

As in the power category, the undervalued players all appear early. In fact, for runs scored they lie even earlier, clustering around the 3^rd  to 7^th rounds. Seven players on this list arise from the 6^th and 7^th rounds alone. Included in this group of players is 2019 batting champion Tim Anderson. Anderson has thus far appeared on both the batting average and speed lists above. I also feel obligated to mention that we find here perennial ATC favorites Josh Bell and Eddie Rosario. More on Rosario (in particular) later on.

As for some later-round players, Carlos Santana (34), Max Kepler (33), Jorge Polanco (33) and Adam Eaton (31) are the profitable players found in the mid-rounds. However, I caution you that other than Eaton, all high runs scored players are being drafted before pick 165. I cannot stress this enough – pick up your runs early this season!

Runs Batted In

The distribution of rounds for RBIsappears quite similar to that of home runs. Undervalued runs batted in are found primarily in rounds 5-7. 14 of the 20 players on this list are being drafted between picks 61 and 105. RBI is another category that needs to be picked up fairly early on.

Upon inspection, there seems to be a large number of first basemen on the list – Josh Bell (37), Jose Abreu (36), Rhys Hoskins (35), Anthony Rizzo (35), Paul Goldschmidt (34) and Carlos Santana (33). You may want to plan on getting your 1B, or even your corner infielder from these three rounds.

Looking at the mid-rounds, included among the undervalued players are Khris Davis and Carlos Santana (both mentioned earlier), as well as Eduardo Escobar. Escobar hit 35 HR last year while knocking in 118 runs for the Diamondbacks. Eligible at multiple positions, Eduardo might be a sneaky good mid-round get for his fantasy owners. If you need to play catch up in RBI, this trio of players can be drafted after pick 135.

Multi-Category Players

Below are the players who appear in multiple top 20 categorical lists above. Once again, these are all undervalued players, are highly productive and are found after round two:

Three names come up as four-category players – Eddie Rosario, Yordan Alvarez, and Javier Baez.

Unfortunately, Alvarez might have some COVID issues to work out. Javier Baez is indeed quite useful as he qualifies upon the stolen base list. However, he is one of the earliest draft selections that we have seen today.

Eddie Rosario at roughly ADP pick 100 seems to have a bullseye on him. A fantasy bullseye! Rosario, who had his best season yet in 2019, saw his ADP drop from last year by almost a full round. Despite being injured last season, Eddie Rosario still hit 32 HR, scored 91 runs, and drove in 109. Last year’s .276 average might even be low for him as his strikeout rate continually sits at just 15%. Rosario is a stable player with second-round upside in the short season – priced at a large discount.

I will also call your attention to Rhys Hoskins. Hoskins is a three-category player found with a late ADP of 127. Rhys is a small launch angle correction away from stardom, and from 40+ HR power (in a full season).

Finally, Adam Eaton is the only three-category player found after pick 200. The only reason why Eaton is being drafted this late is his health risk. However, in a 60-game season - perhaps he can make it to the end unscathed. Consider drafting this highly-skilled World Series champion.

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