Top 25 MLB pitching seasons of all time

Given all of the changes that have taken place in MLB related to pitchers over the year, is it possible to pick out the best 25 seasons of all time?

Take a look at the original rules of the game of baseball, and it would be hard to recognize “pitching.” Throwing overhand was not permitted, and early hitters were allowed to request balls be thrown in certain locations. The number of strikes in for an out and balls for a walk also fluctuated in the early years. What was asked of starting pitchers back in the Deadball Era would make today’s MLB hurlers curl up into a ball.

It was not uncommon in the early days of MLB to see pitchers approach 500 innings and 60 complete games. Comparing seasons from the early 1900s to modern seasons is almost impossible on a numbers-to-numbers basis. Luckily, advanced statistics which attempt to normalize numbers from year to year have been created. They are far from perfect, and many variables make it difficult to compare an MLB pitcher from the 1880s to one today. Attempting to consider as many variables as possible has boiled down the list of all-time great MLB pitching seasons to these 25.

25. Matt Kilroy, 1886

• The Numbers: MLB record 513 strikeouts

Matt Kilroy’s name is one that has faded into the annals of MLB history, but for a brief time in the late 1880s, he was one of the brightest young stars in the league and a true phenom. His 513 strikeouts in his rookie season of 1886 are a record that will never be eclipsed.

Kilroy made his MLB debut in 1886 for the Baltimore Orioles of the American Association. He had begun pitching professionally the year before at the age of 18 after dropping out of school. Kilroy had been on the radar of baseball fans since the age of 14 when he was dubbed “The Boy Wonder.”

The art of pitching in 1886 would be unrecognizable to today’s fans. There was no pitching rubber. A pitcher simply had to deliver the ball from any point within the pitcher’s box so long as he did not cross the line painted 50 feet from home plate. Throwing overhand was also illegal, and hitters took six balls to draw a walk. Kilroy is also credited with throwing three no-hitters during his rookie season, although box scores are questionable at best.

In 1887, the league upped the number of strikes for an out to four. Kilroy responded by winning 46 games, which is still a record for a left-handed pitcher. Over the first two seasons of his career, Kilroy won 75 games, another long-standing MLB record that will never be broken. His effectiveness decreased precipitously after the 1889 season, and Kilroy’s career ended with only 141 total wins.