Inbaseball statistics,bases on balls per nine innings pitched (BB/9IP orBB/9) orwalks per nine innings (denoted byW/9) is the average number ofbases on balls, (orwalks) given up by apitcher per nineinnings pitched. It is determined by multiplying the number of bases on balls allowed by nine, and dividing by the number of innings pitched.[1] It is a measure of the bases on balls ability of a pitcher.
All but one of the top 25 single-season leaders in BB/9IP through 2018 pitched in the period of 1876-84.George Zettlein was the all-time single-season leader (0.2308 in 1876), followed byCherokee Fisher (0.2355 in 1876) andGeorge Bradley (0.2755 in 1880).[2] The highest single-season modern day baseball performance was byCarlos Silva (0.4301 in 2005).[2]
The all-time career leaders in BB/9IP through 2022 wereCandy Cummings (0.4731),Tommy Bond (0.4787), andAl Spalding (0.5114), all of whom played in the 1870s and 1880s.[3]
The active career leaders in BB/9IP through 2022 wereCorey Kluber (1.9683),Michael Pineda (1.9719), andHyun Jin Ryu (1.9914).[4]
