It can be split further into offensive and defensive numbers, but the main focus is to put a single value on a player for their team at their position.
It is called Wins Above Replacement (WAR), pronounced 'Waaar.'
Wins Above Replacement (WAR)
Is an attempt by the sabermetric baseball community to summarize a player’s total contributions to their team in one statistic. WAR looks at a player and asks the question, "If this player got injured and their team had to replace them with a minor leaguer or someone from their bench, how much value would the team be losing?" This value is expressed in a wins format, so we could say that Player X is worth +6.3 wins to their team while Player Y is only worth +3.5 wins.
For offensive players you measure WAR by taking Weighted Runs Above Average (wRAA), Ultimate Base Running (UBR) & Weighted Stolen Base Runs (wSB), and Ultimate Zone Rating (UZR) and adding them together.
Add in a positional adjustment, since some positions are tougher to play than others, and then convert the numbers so that they’re not based on league average, but on replacement level (which is the value a team would lose if they had to replace that player with a “replacement” player – a minor leaguer or someone from the waiver wire).
Convert the run value to wins (10 runs = 1 win) and you have the number.
Ultimate Base Running (UBR) - similar to the outfield arm, whatever credit (positive or negative) is given to an outfielder based on a runner hold, advance, or kill on a batted ball is also given in reverse to the runner (or runners).
Ultimate Zone Rating (UZR) - puts a run value to defense, attempting to quantify how many runs a player saved or gave up through their fielding prowess (or lack thereof).
Pitching WAR uses Fielding Independent Pitching (FIP). Based on how many innings a pitcher threw, FIP is turned into runs form, converted to represent value above replacement level, and is then converted from runs to wins.
Fielding Independent Pitching (FIP) - measures what a player’s ERA should have looked like over a given time period, assuming that performance on balls in play and timing were league average.
Stephen Drew (shortstop)
As he is on the hot seat to not be playing shortstop for the Red Sox in 2014, let us take a look at what his WAR is calculated at. Based on his 2013 season for the Red Sox he is calculated at a 3.4 WAR, meaning we are going to lose 3.4 games without him in the lineup.
There is a further split we can look at based on his offensive WAR and his defensive WAR. He provides an offensive of 3.8 WAR and a defense of 10.9 WAR. Here you see the pain of losing him at shortstop more clearly. The offense we can miss, but the defensive qualities will be tough on the wins.
Jon Lester (pitcher)
If we look at our star pitcher, we see that during his time with the Red Sox he has been between 3.5 - 6.2 WAR. Looking at the last four years we see that he is hovering right around a 4 FIP. We don't want to lose a pitcher that gives you that many wins.
We have not dug deeply, but hope that this overview will give you an idea of one of the more talked about numbers in the baseball statistical world. Soon you will be able to understand the game of baseball, why players are valuable, and when they are not.
If there is something you would like to see covered from baseball statistics, feel free to post a suggestion.
You can catch up on some of the past articles in this series.
Eric is a contributing writer since 2013 and a true Overseas Fan of the Boston Red Sox living in the Netherlands. He's spent years on baseball fields around the world pitching. His weekends are now spent helping the next generations of pitchers to find their passion and love for the sport. More articles by Eric: https://www.redsoxlife.com/search/label/ericschabell