Cannon Arms in 2015

This season, it seems as if every night there’s another highlight of a runner being gunned down trying to take an extra base. In fact, 2015 is on pace to break the record for kills—direct throws to a base to nab a runner—in a single season since Baseball Info Solutions began collecting this data in 2003.

Outfield Arm Runs Saved is a technique to evaluate an outfielder’s arm not only taking into account his ability to kill baserunners, but it also takes into account the fear factor for runners attempting to advance. Here are the leaders so far this season:

Outfield Kills—one component of Outfield Arm Runs Saved—tend to capture everyone’s attention. The second component, Preventing Runner Advancement, shows how an outfielder can impact baserunners by preventing them from advancing in the first place.

Former third baseman Alex Gordon continues to show off his arm in left field, allowing runners to take an extra base on only 17.6 percent of their opportunities. He and Yoenis Cespedes (20.9 percent XBT rate) outperform the field in that statistic, and while they do both have fantastic arms, it helps that they play left field. Because left fielders are closer to third base than either center fielders or right fielders, they allow a lower rate of extra bases taken on average.

Entering the last month of the regular season, these players have the potential to impact pennant races by preventing runners from taking extra bases with the threat of their throwing arms and in turn, preventing extra runs from crossing the plate.