What is OPI in Baseball?
OPI – or On-base Plus Slugging – is one of the most important metrics used in baseball today. It is designed to measure a player’s overall offensive value and is used to compare players across different positions. OPI is a combination of two other metrics, On-base Percentage (OBP) and Slugging Percentage (SLG). Together, they give an indication of a player’s offensive value.
What are On-base Percentage (OBP) and Slugging Percentage (SLG)?
On-base Percentage (OBP) is a measure of how often a batter reaches base on hits, walks, or times hit by pitch. It is calculated by dividing the number of times a player reaches base safely by the number of plate appearances.
Slugging Percentage (SLG) is a measure of the total number of bases a player has earned on hits. It is calculated by adding the number of singles, doubles, triples, and home runs, and dividing by the number of at-bats.
How is OPI Calculated?
OPI is a combination of On-base Percentage (OBP) and Slugging Percentage (SLG). It is calculated by adding the On-base Percentage (OBP) and Slugging Percentage (SLG) and dividing by two.
OPI = (OBP + SLG) / 2
What is a Good OPI?
A “good” OPI is subjective, however, the average OPI for all players is around .350.
- Elite players have an OPI of .400 or higher.
- Very Good players have an OPI between .350 and .400.
- Good players have an OPI between .300 and .350.
- Average players have an OPI between .250 and .300.
- Below Average players have an OPI less than .250.
What Does OPI Tell Us?
OPI is a good indicator of a player’s offensive value. It is a measure of a player’s ability to reach base and drive in runs. A higher OPI indicates that a player is a more productive offensive player.
Limitations of OPI
OPI is not a perfect measure of a player’s offensive value. It does not take into account a player’s speed, defensive ability, or pitching ability. It also does not take into account situational hitting or clutch hitting.
How is OPI Used?
OPI is used to compare players across different positions. It is also used to measure a player’s overall offensive value. Teams will often use OPI to measure how a player stacks up against others at their position, or to determine how valuable a player is for trade purposes.
Who Tracks OPI?
OPI is tracked by a variety of sources, including Major League Baseball, Baseball-Reference, and FanGraphs.
Examples of Players with High OPI
- Mike Trout – OPI of .441 (2020)
- J.D. Martinez – OPI of .425 (2020)
- Mookie Betts – OPI of .421 (2020)
- Freddie Freeman – OPI of .415 (2020)
- Nolan Arenado – OPI of .409 (2020)
Conclusion
OPI is an important metric used in baseball today. It is a combination of On-base Percentage (OBP) and Slugging Percentage (SLG). OPI is used to measure a player’s overall offensive value and is used to compare players across different positions. Teams will often use OPI to measure how a player stacks up against others at their position, or to determine how valuable a player is for trade purposes.