Baseball 101 – Some Numbers to Start With

As I said a few posts ago, my daughter wants me to explain baseball, including “the numbers” to her. I figure that since I want to talk about players and the history of baseball, I should probably explain some numbers up front. if you are a regular baseball fan who knows the numbers and the more modern “numbers” feel free to ignore this post.  For all the rest of you it will be pretty basic and then get a bit more hardcore. This may take a few posts. Here goes:

A win for a pitcher:

A win is usually credited to a pitcher who was in the game when the winning team last took the lead. For a starting pitcher to get a win he usually has to complete at least five innings to get a win. So, if the starting pitcher was pulled after 4 2/3 innings pitched, he won’t get the win.

Since there are 3 outs in an inning, every out is considered 1/3 of an inning. If a pitcher is pulled after one out he has pitched 1/3 of an inning, if pulled after 2 outs then 2/3 of an inning, and if pulled after the third out then he would have completed the inning.

A loss for a pitcher:

A pitcher gets a loss if the runner who scores the winning run was put on base by that pitcher. So, say it is the bottom of the ninth inning and the score is tied 2-2 The starter walks the first batter and the manager pulls him for a relief pitcher. The relief pitcher allows a home run to the next batter and the game ends with the home team winning 4-2. The guy who walked the first batter gets the loss because the 3rd run was all that was needed to lose the game.  Say, though, that the 9th inning begins with the visiting team ahead 3-2 and the home team is up in the bottom of the ninth. Assume the exact same scenario, walk, home run, and game ends 4-3.  Who gets the loss? The relief pitcher this time because the batter he allowed the home run to scored the 4th run that won the game.

Some Batter Numbers

A plate appearance:

Every time the batter comes to the plate, he is credited with a plate appearance. A plate appearance includes an “at bat” but all “at bats” are not plate appearances. A plate appearance includes at bats plus other things like a base on balls or a sacrifice hit. I will explain that below. You should also note the following scenario. A player is at bat and a runner is picked off a base or caught stealing. The batter does not get a plate appearance.

An at bat:

This is a completed plate appearance by a batter, except for when a plate appearance results in a base on balls or a sacrifice (a bunt or a fly ball that advances a runner). Abbreviated AB.

Batting Average:

You calculate this by taking the number of base hits a player gets and divide it by his at-bats.  So, last year David Ortiz had 518 ABs and 160 hits (38 doubles, 2 triples, 30 home runs, and 90 singles). Divide 160 by 518 and you get: .309.

On Base Percentage/OBP:

This is different then batting average and a better indicator of a player’s offensive value because it counts walks and hit by pitches.  So here it is:

OBP = Hits (H) + Bases on Balls (BB + Intentional BB) + Hit by Pitch (HBP) / At Bat (AB) + BB + HBP + Sacrifice Flies (SF)

David Ortiz again: 160 + (76 + 27 – Papi lead the league in intentional walks last year) + 1 /518 + 103 + 1 + 5 = .395.

You can figure out what the OBP for the league was by adding all the players stats together. That would be quite a pain to do. Fortunately, there is a website for all the baseball number nerds like me – – which calculates all these things for you so you don’t have to.

Just to give you a sense of where Papi stands. The league average OBP last year was .318. Papi’s OBP was .077 percentage points better then the league. That is quite a bit. The league leader in OBP last year was Miguel Cabrera of the Tigers at .442. Think of it this way, Cabrera is getting on base nearly 45% of the time he steps to the plate.

The top three best OBP seasons ever:

  • Barry Bonds .609 in 2004
  • Barry Bonds .581 in 2002
  • Ted Williams .552 in 1941

Slugging Percentage:

Total bases divided by at-bats.

How do you figure out total bases? Well, you award values for each hit – singles, doubles, triples and home runs. Each single gets 1 point, each double 2 points, each triple 3 points, and each home run 4 points. So, say Papi went 2-4 during a game with a double, a ground out, a strike out and a home run. He gets 2 points for the double and 4 points for the home run for a total of six total bases during the game.

Papi had 292 total bases last year. You divide that by at bats and you get .564. That is pretty good. It was third best last year behind Miguel Cabrera (.636) and Chris Davis (.633). You can probably guess that guys who hit a lot of home runs have a pretty high slugging percentage. The top three highest single season slugging percentages ever?

  • Barry Bonds .863 in 2001
  • Babe Ruth .847 in 1920
  • Babe Ruth .846 in 1921

On Base Percentage Plus Slugging (OPS):

Pretty straight forward, add OBP and Slugging together.

Papi’s for 2013 was .959 (.395 + .564).

OPS + (also known as adjusted OBP):

A newer stat. It is OPS adjusted for the park and the league in which the player played. It does not consider a player’s position – say a 1B versus a 2B. An OPS + of 100 is considered league average, 125 is very good and 150 is excellent.  If you want to know the math, it is OBP/league average OBP + SLG/league average SLG and then you subtract 1. There would be a couple more parens in there if you really wanted to know the math.  You then take that number and multiply it by 100.

Both the league average slugging and OBP are adjusted to take the ball park into account; it is easier to hit in some parks as opposed to others – think Coors Field in Denver where the air is thinner and ball can travel 10-15 feet further. I have no idea how the stat guys calculate park effects. Well, I do a little but not enough. But they can do it and you can understand why. It helps to adjust a players stats to compare players in parks that are easy to hit homers in (for example) and parks where homers are harded to come by.  You just need to know that 100 is the average for an MLB player.

Papi’s OPS+ last year was 160. Miguel Cabrera led that majors with an OPS+ of 187.

All time best single season OPS+:

  • Barry Bonds 268 in 2002
  • Barry Bonds 263 in 2004
  • Barry Bonds 259 in 2001

Do you get a sense why Barry Bonds and steroids are such a hot topic? He leads many all-time best ever seasons. Was it all him or partly the steroids? Discussion to be had later.

WAR (Wins Above Replacement):

This is a number that tells you the value (ie. number of wins) a player added to his team above what a replacement level player (someone who might be a career AAA player or someone who goes in and out of the majors, also known as a AAAA player; AAA is the highest level of the minors, so a AAAA player does not really exist as a league; he would just be someone who goes between minors and majors but just quite can’t stick in the majors).

It is way to complicated to explain and I can’t say I fully understand how they come up with WAR. It is a helpful number, though, in comparing players and understanding worth as it relates to salary. There is some indication that a win in 2013 is worth about $5 million dollars to a baseball team.There are different baseball stat sites that calculate WAR a bit differently – and to name two. I am using baseball-reference WAR most of the time.

Papi’s WAR last year was 4.4. The WAR leader in the AL last year was Mike Trout at 9.2. Papi’s salary last year was $14 million; using WAR you could argue that the Sox made money on Papi last year. His 4.4 WAR made him worth about $22 million.

Best WAR for a season?

  • Babe Ruth 14.0 1923
  • Babe Ruth 12.9 1921
  • Babe Ruth 12.4 1927
  • Yaz 12.4 1967

Okay, that’s enough for today.  We’ll do some pitching stats next time.


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