MLB Team ERA vs OPS Chart

Calculation

ERA = (Earned Runs ÷ Innings Pitched) × 9

ERA measures a pitcher's effectiveness by calculating how many earned runs they allow per nine innings pitched. Only runs scored without the benefit of defensive errors are counted as "earned."

Historical Context

ERA was first developed and used in the early 1900s to provide a more accurate assessment of a pitcher's performance apart from their team's fielding abilities. Henry Chadwick, considered the "Father of Baseball," is often credited with developing many early baseball statistics including elements that evolved into ERA. The statistic gained prominence in the 1910s under American League President Ban Johnson and became official in 1912.

The "Dead Ball Era" (1900-1919) saw ERAs commonly below 2.50, while the modern MLB has seen average ERAs typically range from 3.80-4.50. Hall of Famer Ed Walsh holds the career record with a remarkable 1.82 ERA, while the single-season record belongs to Dutch Leonard's 0.96 ERA in 1914.

Calculation

OPS = On-Base Percentage + Slugging Percentage

Where:

• On-Base Percentage (OBP) = (Hits + Walks + Hit By Pitch) ÷ (At Bats + Walks + Hit By Pitch + Sacrifice Flies)
• Slugging Percentage (SLG) = Total Bases ÷ At Bats
• Total Bases = Singles + (Doubles × 2) + (Triples × 3) + (Home Runs × 4)

Historical Context

While its component statistics (OBP and SLG) have been tracked since baseball's early days, OPS as a combined metric emerged in the 1970s and gained mainstream popularity during the sabermetric revolution of the 1980s. Branch Rickey and Allan Roth pioneered OBP in the 1940s, recognizing the importance of reaching base beyond just hits.

Pete Palmer and John Thorn helped popularize OPS in their 1984 book "The Hidden Game of Baseball," and it became more widely adopted when the statistics were included on the backs of Topps baseball cards starting in 2004. Babe Ruth holds the career record at 1.164, while Barry Bonds' 1.422 mark in 2004 is the single-season record.