Popularized in the book and later on the movie, Moneyball, Sabermetrics is “the search for objective knowledge about baseball.’ Thus, sabermetrics attempts to answer objective questions about baseball, such as ‘which player on the Red Sox contributed the most to the team’s offense?’ or ‘How many home runs will Ken Griffey hit next year?’ It cannot deal with the subjective judgments which are also important to the game, such as ‘Who is your favorite player?’ or ‘That was a great game.'” -Bill James.
Sabermetrics has caused tremendous controversy among sports analysts and enthusiasts because of the positions they take on questions such as: How do we reconcile mathematical knowledge that contradicts our intuition? What if our eyes tell us one truth and our numbers tell us a different one?
Some people complain that the reliance on numbers takes away from the “magic and mystery of the game.”
The baseball organizations themselves have adopted the data driven approach to analyzing players. With the success of the Oakland Athletics (a team that was an early adopter of the mathematical methods known as Sabermetrics) and later on the Boston Red Sox, most if not all teams use these analytical methods.
The first link below is an introduction to the basics of sabermetrics and below that are two disagreeing with its use.