In 2003 Michael Lewis’s book Moneyball—an inside look at the Oakland Athletics and their general manager Billy Beane—was published. Beane had earlier served as an understudy to Athletics general manager Sandy Alderson, who had read James’s Baseball Abstract while constructing a roster that won three straight American League (AL) championships beginning in 1988. Alderson introduced Beane, an ex-player, to the Baseball Abstract in the mid-1990s. “[T]hat was the big moment,” Beane recalled, “when I figured out that all the stuff Sandy was talking about was just derivative of Bill James.”

The runaway commercial and artistic success of Moneyball (which became a hit movie nearly a decade later) spurred a number of major-league owners and executives to take sabermetrics more seriously, and over the next few years there was a rush to hire sabermetricians, many of whom first wrote for numbers-oriented Web sites like Baseball Prospectus, FanGraphs, and The Hardball Times. Among these sabermetricians’ duties was parsing the incredible wealth of data provided to the teams—and, to some degree, the public—by a company called Sportvision, which set up cameras in every stadium and tracked just about everything that might be recorded. The amount of data compiled by technology systems known as PITCHf/x, HITf/x, COMMANDf/x, and FIELDf/x was astounding. However, by 2015, a new camera-based tracking system had been installed in every Major League Baseball (MLB) stadium, and the resulting output, dubbed Statcast, provided the teams—and, to a lesser degree, amateur and professional analysts outside of front offices—with a wealth of new information that allowed unprecedented accuracy of measuring virtually everything that happens during a baseball game. This data was enough to keep teams of number crunchers busy, leading to a sort of arms race as front offices attempted to scoop up bright young analysts to work with the data.

By 2012 essentially all of MLB’s 30 franchises employed at least one sabermetrician, although there was a wide range of emphasis placed by management on the work of those employees. In 2008 the Tampa Bay Rays, relying heavily on sabermetrics, went from perennial AL doormats to perennial contenders, qualifying for the postseason three times in four years. Meanwhile, the San Francisco Giants won championships in 2010, 2012, and 2014 while giving relatively short shrift to modern analysis.