Strikeout rate

Going to a sports card shop is surely an interesting thing to do. You can pull baseball cards that are newly released, at the same time, you can also find something that brings you back to the past. I found a topps league leaders card, on the front is the 1999 NL strikeout leader Randy Johnson, on the back is 1999 AL strikeout leader Pedro Martinez. Each threw more than 300 strikeouts in 1999 and both of them are Hall of Famers.

In Randy Johnson’s legendary 22 seasons in the MLB, he had 6 seasons with throwing at least 300 strikeouts. In particular, he threw 372 strikeouts in 2001, 11th most strikeouts in a single-season in baseball history. Meanwhile, Pedro Martinez had two seasons with at least 300 strikeouts. In their careers, Pedro Martinez threw 3154 strikeouts and Randy Johnson threw 4875 strikeouts. Only 4 pitchers had more than 4000 strikeouts in their careers. Randy Johnson had a strikeout rate of 28.6% in his career and Pedro Martinez’s strikeout rate was 27.7%.

Strikeout rate has been discussed recently since Theo Epstein, who announced his decision to step down as Chicago Cubs’ President of Baseball Operations, indicated that the strikeout rate was a little bit out of control.

Let’s start from 1999 since the baseball card was the 1999 league strikeout leaders. In 1999, the strikeout in the big league was 16.4%. It went up to 17.3% in 2001 and remained below 17% from 2002 to 2006. However, the strikeout rate has gone up since 2007. It started from 17.1% in 2007 and reached 23.4% in the 2020 season. In 2014, it was the first time that the league strikeout rate went above 20%.

If we look at baseball history, we surely can understand what Theo Epstein said. The strikeout rate first went up to 15% in 1963 and then it stayed above 15% for several years. Nonetheless, the strikeout rate dropped to 14.3% in 1971 and it had remained below 15% for more than 10 years. Until 1986, the strikeout rate rose to 15.4% and it remained approximately 15% for almost a decade. After the 1994-95 MLB strike, strikeout rate reached 16.2% in 1995 and it was the first time to see a strikeout rate higher than 16%. Two years later, it reached 17.1%. In 2009, the strikeout rate jumped to 18% and has kept rising. It might not be just “a little bit” out of control.
Baseball is not exactly the same as we watched ten or twenty years ago. We see that strikeout rate goes up gradually, however, from 2000 to 2020, we only see 9 times that a pitcher threw more than 300 strikeouts in a single season. The way of pitcher usage has changed and the way to evaluate a player has changed. Baseball has changed, indeed. There are several elements in baseball. Strikeout is just one of those elements. A higher strikeout rate means that there are fewer balls in play. Do fewer balls in play decrease the quality of the game and make baseball less entertaining? Fans will tell.