Daily Projections by SaberSim on FanGraphs!

Daily projections courtesy of SaberSim.com are now available on the player pages and in a sortable format!

Matt Hunter, creator of SaberSim.com, explains the projections:

FanGraphs has long been home to a variety of excellent projection systems, each with its own distinguishing features that attempt to predict future performance as effectively as possible. Though these systems differ from one another in many respects, one common trait is that they project performance over an extended period of time—season, rest of season, or even multiple seasons. Beginning this week, FanGraphs will also feature a daily projection for each player. The daily projections are created by SaberSim, and are updated each day to reflect the specific factors the player will encounter in the matchup at hand.

SaberSim, as the name suggests, utilizes simulation to produce player and team projections. By simulating – thousands of times – every event of a particular game, the simulator is able to account for the unique context of each game and the interaction between players, using the actual posted lineups and starting pitcher assignments. It starts with Steamer rest-of-season projections (including handedness splits) for each player, then adjusts the probability of each event based on a number of context-specific factors. These include: regressed home-plate umpire strikeout/walk tendencies, handedness- and event-specific park factors, game-time temperature and wind speed/direction, home/away splits, and perhaps most importantly, batter-pitcher matchups using the Odds Ratio method. The adjusted rates are then fed into the simulator, which keeps track of the outcome of each play and the statistics for each player over the course of the simulated games.

The daily projection for every player in a starting lineup on a given day is featured towards the top of his player page, and the full leaderboard can be found in the Projections page linked above. The projections consist of the mean number of each outcome a player produced over the course of thousands of simulated games. Therefore, the numbers displayed do not represent the probability of each event happening, but rather the average number of times it happened per simulated game.

A quick note on these projections: the simulator currently only runs games with a single starting lineup for each team – for lineups that aren’t yet posted, we use the team’s most recent lineup vs. the opposing pitcher’s handedness. This means that until lineups are officially posted, you may not see projections for all players – if, for example, a player had a day off the day before. Because of this, the projections are most accurate and useful after all lineups from a given game are official. Usually this occurs about 4-5 hours before start time.

Over the past year and a half, SaberSim has grown from a basic simulator to an advanced tool for projecting daily performance on an individual and team level. While all player projections can be found right here on FanGraphs, you can find additional data and tools, such as specific team and player distributions and a daily fantasy lineup optimizer, on SaberSim.com. We look forward to sharing these daily projections with the FanGraphs community over the days and weeks to come, and welcome any comments, criticisms, or suggestions as we continue to improve the effectiveness of the simulator and the site. Enjoy!

We hoped you liked reading Daily Projections by SaberSim on FanGraphs! by David Appelman!

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David Appelman is the creator of FanGraphs.

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Bob
Guest
Bob

Take the Rockies @ Mets game on 8/10…

SaberSim has the win % as 41.8 / 58.3
Fangraphs has the win % as 51 / 49

I’m trying to figure out why? Jonathan Gray according to SabrSim is worth .3 wins and Jon Niese is worth .4 wins. My eyeball test would have to think the Rockies lineup is slightly stronger (at worth even) with the Mets.

What accounts for the nearly 10% difference? Is fangraphs using the pre-Uribe/Johnson/Cespedes lineup?

Bojan
Guest
Bojan

My eyeball test would have to think the Rockies lineup is slightly stronger (at worth even) with the Mets.

Average 2015 wRC+ for the current Rockies starters is ~102. For the Mets it’s ~112

Bob
Guest
Bob

Any opinion why fangraphs/SabrSim are off by 10% in this example?

Bojan
Guest
Bojan

Perhaps assuming different lineups? Perhaps (not) taking into account the handedness of the starting pitcher?

Matt Hunter
Member
Member

As David said, I’m seeing the Mets at 54.3% right now. There are a number of factors that could influence the difference. We may be using different projected lineups (though once the lineup is posted officially, they will be updated to use the same). SaberSim also accounts for umpire and weather, and uses only Steamer splits projections, rather than Steamer and ZiPS combined, so that could have a significant effect. Once the official lineups are posted, we may see the odds converge.