What is this? A Statcast metric designed to express the skill of pitchers at preventing base runners from advancing on the bases, via steal attempts or pickoffs/balks.

How this works: Each steal opportunity (currently runners at 1B only) is assigned a probability of being successful or not based on several inputs about the situation, most notably the speed of the runner. “Lead distance gained” expresses the distance gained by the runner between the pitcher’s first move and the release of the pitch.

How to read it: Pitcher Base Advances Prevented is the difference between advances allowed (vs. avg) and outs created (vs. avg). Pitcher Stealing Runs is a translation of that to a run value, where an advance allowed is -.2, an out created is +.45, and opportunities where a runner did not attempt to run are given a sliding scale based on the situation.

To be qualified a pitcher must have at least one stolen base opportunity per team game. A stolen base opportunity is defined as a pitcher thrown with a runner on first (and no other runners on).