Monday, August 8, 2011

Why the Red Sox have Mariano Rivera's number

Uniquely, [Mariano Rivera] did all of it with one pitch, a low- to mid-nineties cut fastball... Depending on their role, most pitchers require a repertoire of two to four pitches to succeed, but for Rivera, that one pitch has been enough for him to compile an almost certain Hall of Fame career. ...

In 2004, not including the postseason, the [Red] Sox batted .250/.375/.375 (average/on-base percentage/slugging percentage) and handed Rivera a 4.22 ERA while the rest of the league could only muster .221/.271/.265, a 1.59 ERA. The year before that the Sox hit .356/.396/.467 (a 2.70 ERA); everyone else hit .209/.246/.265 (1.48 ERA).

Due to the unbalanced schedule, the Sox see Rivera quite often. ... Against the thirteen teams he faced fewer than six times [in 2004], he allowed an ERA of 0.45 in 40 innings; against the other three: 3.59 in 38.2. ... The trend held true in 2003 as well. ...

Interestingly, and contrary to the league norm, Rivera's success diminished the more often he saw a team. Most pitchers' ERAs improved the more familiar they were with a team and its lineup. ... Rivera's ERA decline is likely related to his reliance on a single pitch.
--James Click, Mind Game: How the Boston Red Sox Got Smart, Won a World Series, and Created a New Blueprint for Winning, on the cost of one-trick ponies