Glossary: Base Running

Number of times a player was involved in one of the following situations:

• Runner on first with second and third unoccupied, less than two outs, a line drive, pop-up, or fly ball is caught by an outfielder
• Runner on second but not third, less than two outs, a line drive, pop-up, or fly ball is caught by an outfielder
• Runner on third with other bases optionally occupied, less than two outs, a line drive, pop-up, or fly ball is caught by an outfielder

Baserunning Runs. Measures the number of runs contributed by a player's advancement on the bases, above what would be expected based on the number and quality of the baserunning opportunities with which the player is presented, park-adjusted and based on a multi-year run expectancy table. BRR is calculated as the sum of various baserunning components: Ground Advancement Runs (GAR), Stolen Base Runs (SBR), Air Advancement Runs (AAR), Hit Advancement Runs (HAR) and Other Advancement Runs (OAR).

Here is an example of the Baserunning Runs spectrum based on the 2011 season:

Excellent - Ian Kinsler 11.6
Great - Coco Crisp 4.3
Average - Bobby Abreu 0.0
Poor - Casey Kotchman -4.4
Horrendous - Ryan Howard -9.4


Note: Credit/blame for Double plays is not ascribed to either batter or runner(s) via BRR. Hence Manny Machado can lead MLB in GIDP in 2018 yet have almost +1 BRR. Or Tommy Pham with 18 GIDP in 570 PA and almost +5 BRR.

Air Advancement Runs. The number of theoretical runs contributed by a baserunner or baserunners above what would be expected given the number and quality of their baserunning opportunities. AAR is based on a multi-year Run Expectancy matrix, is park adjusted, and considers the following scenarios:

• Runner on first with second and third unoccupied, less than two outs, a line drive, pop-up, or fly ball is caught by an outfielder
• Runner on second but not third, less than two outs, a line drive, pop-up, or fly ball is caught by an outfielder
• Runner on third with other bases optionally occupied, less than two outs, a line drive, pop-up, or fly ball is caught by an outfielder

Here is an example of the Air Advancement Runs spectrum based on the 2011 season:

Excellent - Alex Gordon 2.68
Great - Robinson Cano 1.21
Average - Brian Bogusevic 0.00
Poor - Yorvit Torrealba -1.43
Horrendous - Adrian Gonzalez -2.28

Ground Advancement Runs. The number of theoretical runs contributed by a baserunner or baserunners above what would be expected given the number and quality of baserunning opportunities. GAR is based on a multi-year Run Expectancy matrix and considers the following scenarios:

• Runner on first only with less than two outs, ground ball or bunt is hit to an infielder where a hit or an error is not credited
• Runner on second only with less than two outs, ground ball or bunt is hit to an infielder where a hit or an error is not credited
• Runner on third only with less than two outs, ground ball or bunt is hit to an infielder where a hit or an error is not credited

Here is an example of the Ground Advancement Runs spectrum based on the 2011 season:

Excellent - Emilio Bonifacio 6.45
Great - Dexter Fowler 2.98
Average - Roger Bernadina 0.01
Poor - Adrian Gonzalez -1.76
Horrendous - Ryan Howard -3.76

Hit Advancement Runs. The number of theoretical runs contributed by a baserunner or baserunners above what would have been expected given the number and quality of opportunities. HAR considers advancement from first on singles, second on singles, and first on doubles and is adjusted for park and based on a multi-year Run Expectancy Matrix.

Here is an example of the Hit Advancement Runs spectrum based on the 2011 season:

Excellent - Dexter Fowler 4.74
Great - Ryan Braun 2.69
Average - James Loney 0.00
Poor - Brett Wallace -2.54
Horrendous - Ryan Howard -5.66

Other Advancement Runs. Measures the number of runs contributed by a player's advancement on the bases, above what would be expected based on the number and quality of the baserunning opportunities with which the player is presented. Other Advancement takes into consideration a player's opportunities and advancement on the basepaths due to wild pitches and passed balls. The run value of this advancement is based on a multi-year run expectancy matrix and park-adjusted.

Here is an example of the Other Advancement Runs spectrum based on the 2011 season:

Excellent - Bobby Abreu 0.92
Great - Angel Pagan 0.40
Average - Drew Stubbs 0.05
Poor - Juan Uribe -0.28
Horrendous - Michael Cuddyer -0.72

Equivalent Stolen Base Runs. The number of theoretical runs contributed by a baserunner or baserunners above what would be expected given the number and quality of their baserunning opportunities. EqSBR is based on a multi-year Run Expectancy matrix and considers both stolen base attempts and pick-offs.

Here is an example of the Stolen Base Runs spectrum based on the 2011 season:

Excellent - Tony Campana 2.82
Great - Dustin Pedroia 1.32
Average - Brandon Phillips -0.01
Poor - Jason Bartlett -1.06
Horrendous - Jon Jay -1.91

Ground advancement opportunities: number of times a baserunner was involved in one of the following situations:

• Runner on first only with less than two outs, ground ball or bunt is hit to an infielder where a hit or an error is not credited
• Runner on second only with less than two outs, ground ball or bunt is hit to an infielder where a hit or an error is not credited
• Runner on third only with less than two outs, ground ball or bunt is hit to an infielder where a hit or an error is not credited

Hit advancement opportunities: number of times a runner could have gone from first to third on a single, first to home on a double, or second to home on a single.

Other advancement opportunities: number of opportunities to advance on wild pitches, passed balls, and balks.

Percentage of stolen base attempts that are successful.

Net Stolen Bases, or SB - CS.

Stolen base opportunities: SB + CS + Pickoffs.