Every time baseball season rolls around, you can expect a hearty serving of alphabet soup.
What’s the difference between BB and OBP? OBP vs. OPS? Is it a bad thing if someone has a large WHIP or are we more concerned with the league of ERA a player is in? Does any of it even matter?
Here is a quick-hits list of baseball terminology to sift through whenever someone challenges your “true fandom.”
Let’s start with the offense: BA, BB, OBP, SLG and WAR. BA stands for “batting average,” which is how often a player reaches base via a hit. For example, Boston Red Sox outfielder Mookie Betts led the American League last year with a .346 batting average (180 hits in 520 at-bats), meaning roughly that he would get one hit out of every three at-bats. BB stands for “base on balls,” or a walk. To record a walk, a player must accrue 4 balls (aka 4 pitches outside of the strike zone that they did not swing at) in one at-bat. So, if a player has a BB next to an at-bat, they drew a walk. By combining BA and BB, you get OBP, or “on-base percentage.” This calculates how often a player reaches base, whether by hit or walk. Continuing with the same player, Mookie Betts had a .438 OBP last season, meaning he was likely to reach base around 4 out of every 10 times he was up to bat.
Now, some may note that in baseball you can hit more than just singles — you can hit doubles, triples and home runs. These are calculated into SLG, or a “slugging percentage.” The higher a player’s slugging percentage, the more likely they are to get extra-base hits (doubles, triples, etc.)
And now, the defense. The most important player on defense will always be the pitcher, because they will be involved in every single at-bat. A pitcher’s most-cited stats are usually ERA, WHIP, K/9, BB, K and W/L. BB is still base on balls, so it still calculates walks. W/L are “wins and losses;” pitchers “win” or “lose” games if their team is leading or trailing at the time they’re pulled from a game. If the two teams are tied when a pitcher is removed, it goes down as a no decision. K stands for a strikeout (three strikes and you’re out).
ERA stands for “earned run average,” which is the average number of runs a pitcher will give up per nine innings. For example, if a pitcher has an ERA of 3.45, that means through all his innings pitched so far he has given up about 3 ½ runs per game. WHIP stands for “walks and hits per inning pitched.” Wordy, but the formula calculates the average of base runners a pitcher will allow in any given inning (every baseball game is at least nine innings). The lower the WHIP, the less likely a baserunner.
Which brings us to WAR: “wins above replacement.” This calculates a players value in comparison to the league average by how many wins he adds to his team over the course of the season. So Mookie Betts (WAR of 10.9) was worth roughly 11 wins to the Boston Red Sox last season.
An important thing to remember about all of these stats: They are not predictors. Baseball stats are summations of past actions and offer a statistical pattern of activity.
A helpful tool to any hopeful baseball stathead is Baseball Reference. The website is generally accepted as the best source for all things baseball, dating back to the 19th century.