MLB DFS: Stack 'Em Up

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I remember the first time I ever played MLB DFS. Making that initial roster was exciting but fairly daunting. I had no idea who to pick or how to evaluate matchups, which left me clumsily crafting a roster full of one-off players that fit within the salary cap.

As I got more entrenched into the DFS community, I started learning about the concept of stacking. It’s come to the point now where it’s second nature to me and the first thing I do for each MLB slate is review the Vegas lines and try to identify my favorite stacks. The concept of stacking made sense – roster several players from the same team because if that team goes off, you get all the goodness.

This year, I’ve noticed stacking more than ever. It seemed like every night, the winning GPP team had done some combination of a 4-4 stack (meaning they played 4 players from one team and 4 players from another team). Sometimes I would see a 4-3-1 or 5-3 stack take down a GPP. But on some rare occasions, I’d see a team take down a GPP with no stacking. In fact, the team almost feels like it was haphazardly mashed together with no rhyme or reason, yet somehow consisted of a collection of players who did enough to win a tournament.

So it led me to ask the question – do I keep stacking because that’s what conventional wisdom has told me is the best DFS strategy, or should I deviate from stacking in an effort to zig when others are zagging? I’ve been really interested in this question of whether to stack or not, so I started digging into it. I will admit, I had trouble figuring out where to even begin. How do I quantify whether stacking is beneficial or not? So I took a step back and asked myself a simple question: what is the ultimate goal of every slate I play in? Let me personalize that question: what is your ultimate goal of every slate you play in? The answer will vary by person, but here’s the answer I came to: my ultimate goal should be to score the most points within the salary cap. It’s a simple answer, really, but it’s rarely one I tell myself on a daily basis.

Given that the goal should be to score the most points, I started digging into perfect lineups. A perfect lineup is the lineup that would have scored the most points that day within the given salary cap. I struggled with this for a long time because realistically, nobody ever hits the perfect lineup on a given slate. Baseball is filled with so much variance that to roster Andres Blanco when he mashes a home run against Max Scherzer AND roster Brandon Moss when he goes 4-for-5 with a home run off Shelby Miller AND roster Avisail Garcia when he hits a home run batting seventh in the order AND… (okay I’ll stop, but you get the picture, it’s darn near impossible). Despite this, studying perfect lineups seemed to make the most sense in trying to understand the value of stacking because perfect lineups remove any factors associated with the buy-in cost. You can’t analyze the winning lineup of the Thunderdome to the winning lineup of the Quarter Arcade because how you approach roster construction when $5,300 is on the line is very different than when $0.25 is on the line. If I had to guess, the winning Thunderdome teams tend to have fewer points than the winning Quarter Arcade teams due to the fact you can afford to take on more risk and reach for that Andres Blanco homer game when all you have to lose is a quarter.

So with that being said, I looked at all 179 main slate perfect lineups for DraftKings in the 2016 MLB season. On DraftKings, you have the ability to stack up to five players from a single team. If there’s interest in the future, I’d be open to looking at it for FanDuel or FantasyDraft, and for the 2017 season. Here’s what I found:

The Types of Stacking

As I combed through the 179 main slate perfect lineups, I broke down each lineup into whether there were any player stacks. To help you visualize what it might look like, here’s an actual perfect lineup (which was the one I referenced above):

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In this perfect lineup, we see a case where there are three pairs of teammates in the perfect lineup, or in other words, a 2-2-2 stack.

Here’s the distribution of stacks that manifested in the 179 main slate perfect lineups:

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What this is saying is that in 26.8% of perfect lineups, a 2-man stack existed, with the 6 remaining position players being from different teams. In fact in 13.4% of perfect lineups, there was no stacking involved. I found it interesting that 12.3% of perfect lineups had a 3-man stack, but only 2.8% had a 4-man stack, and only a single lineup had a 5-man stack. This finding stood out to me because I have an awful habit of trying to make my stacks into the 4-4 or 5-3 variety. I can rarely get myself to play 4-3-1 or 5-2-1 stacks because that one oddball drives me crazy (it’s the OCD in me). These findings seem to suggest that maybe I need to stop forcing myself into playing 4-4 or 5-3 stacks and instead be more open to findings pairs or trios of teammates across multiple teams.

One other takeaway for me is that 86.6% of perfect lineups from last season had a stack of some sort, even if it was just a 2-man mini stack. So there’s definitely validity in stacking. But the 13.4% of perfect lineups that had no stacking involved also intrigued me, because it means there’s no one way to approach GPPs. If you hit on the right one-off plays, you could take down a GPP.

Does Size Matter?

As I dug into this data, I was curious if slate size had an impact on the results. My initial hypothesis was that on huge slates, it’s more likely that a perfect lineup will consist of no stacking because there are more chances of players having breakout games. And on shorter slates, it probably makes sense to incorporate some kind of stacking given the correlation of teammates and the hope one or two teams just explode.

I reran the graph from above, but in the second column calculated the average number of games on the slate for that type of stack:

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The findings did match my hypothesis. What we see is that as the slates get smaller, there are generally more instances of stacking. Again, this makes sense, because if you’re playing a small 5-game slate and you happen to stack the team that goes off for 20 runs, players from that team will likely be in the perfect lineup.

Conclusion

I should caveat that we’re only working with a 179 game sample and the findings from 2016 may not be predictive or indicative of what’s going to happen in 2017, but it was nice to be able to have data to work with. My takeaways are the following:

1. Stacking does appear to be the way to go in GPPs, but don’t ever pigeonhole yourself into thinking stacking must be of a certain format (ex: 4-4, 5-3, etc.).
2. On shorter slates, it does seem that stacking becomes more important.
3. The number of 4- and 5-man stacks in perfect lineups was surprisingly low to me.
4. Don’t be afraid to play Andres Blanco against Max Scherzer (just kidding, sort of). Check out the BvP later!

You can find me on Twitter here. I’d love to hear your thoughts on stacking in the Comments below. Thanks for reading.

About the Author

fathalpert
Allan Lem (fathalpert)

Allan Lem (aka fathalpert) began playing fantasy sports in high school and transitioned to DFS in 2015. He graduated from UC Berkeley with a degree in Economics and lives in California with his wife and two kids. Allan got his break in the industry covering Preseason NBA content. He is currently the Social Media Manager for RotoGrinders, ScoresAndOdds, and FantasyLabs. Follow Allan on Twitter – @AllanLemDFS