I
Beginner
The Rules of Baseball in Ten Minutes
Never watched a game in your life? Start here. Everything you need to follow an inning, in plain language.
6 min
Apr 2
Apr 2
The academy
Learn baseball, from first pitch to sabermetrics.
Free, structured lessons on the rules, the statistics, and the strategy behind the most data-rich sport in the world.
Start here
1The Rules of Baseball in Ten MinutesBeginner · 6 min2The Field: A Tour of the DiamondBeginner · 6 min3How an At-Bat Works: Balls, Strikes, and the CountBeginner · 6 min4The Nine Positions and What They DoBeginner · 6 min5The Three Outs: How a Half-Inning EndsBeginner · 6 min6Baserunning and Scoring: How Runs Are MadeBeginner · 6 min7Innings, Lineups, and the Flow of a GameBeginner · 6 min8How to Read a Box ScoreIntermediate · 7 min9Hitting Stats: AVG, OBP, SLG, OPSBeginner · 6 min
Fundamentals
II
Beginner
The Nine Positions and What They Do
Pitcher, catcher, four infielders, three outfielders. A quick tour of who stands where, and why it matters.
6 min
Apr 5
Apr 5
III
Beginner
The Field: A Tour of the Diamond
Before the rules make sense, you need the map. Home plate, the bases, the mound, fair and foul — where everything lives.
6 min
Apr 6
Apr 6
IV
Beginner
How an At-Bat Works: Balls, Strikes, and the Count
The duel at the heart of the game — what the strike zone is, how the count works, and the two ways an at-bat ends.
6 min
Apr 8
Apr 8
V
Beginner
The Three Outs: How a Half-Inning Ends
A team bats until it makes three outs. Here are the everyday ways the fielding side records them.
6 min
Apr 10
Apr 10
VI
Beginner
Baserunning and Scoring: How Runs Are Made
Getting on base is only half the job. Here is how runners move, steal, and come home to score.
6 min
Apr 11
Apr 11
VII
Beginner
Innings, Lineups, and the Flow of a Game
Nine innings, two halves each, nine hitters in a fixed order. How a full game unfolds from first pitch to final out.
6 min
Apr 13
Apr 13
VIII
Beginner
A Primer on Major League Baseball
Thirty teams, one hundred and sixty-two games, six months of summer. A short field guide to the most statistical sport in the world.
5 min
Apr 12
Apr 12
IX
Intermediate
How to Read a Box Score
The box score is baseball’s daily ledger. Once you can read it, you can reconstruct a game you never saw.
7 min
Apr 15
Apr 15
Statistics
X
Beginner
Hitting Stats: AVG, OBP, SLG, OPS
Four numbers describe almost any hitter. Learn what each one rewards — and why on-base percentage quietly matters most.
6 min
Apr 20
Apr 20
XI
Intermediate
Reading Pitcher Stats: ERA, WHIP, FIP
Three numbers tell you almost everything about a starting pitcher. Two of them lie. Here is how to read the one that does not.
7 min
Apr 24
Apr 24
XII
Advanced
Beyond the Card: wOBA, wRC+, and WAR
When AVG and OPS run out of road, sabermetrics take over. The three numbers that front offices actually argue about.
8 min
Apr 28
Apr 28
Strategy
XIII
Intermediate
The Shape of Variance: Why a 70% Call Still Loses
A high-confidence call that loses is not a broken model. It is, in fact, a confirmed model. Here is why.
6 min
May 1
May 1
XIV
Intermediate
The Modern Bullpen and the Times-Through-the-Order Penalty
Starters used to finish what they began. Now the most important pitching decision often happens in the sixth inning.
7 min
May 5
May 5
XV
Intermediate
Park Factors: Why the Stadium Matters
The same fly ball is a home run in one park and a routine out in another. Geography is a hidden variable in every game.
6 min
May 9
May 9
XVI
Beginner
Responsible Prediction: The Case for a Public Ledger
Anyone can post a winner. Only the analyst who posts every loser too is telling the whole truth.
5 min
May 13
May 13
The Ra Model