The Book: Playing the Percentages in Baseball "The disruptive runner has an enormously negative influence on the batter, enough to almost completely offset the disruption caused to the defense." They estimate the total gain is .002 points of wOBA. Meanwhile, I seem to recall other studies that point towards it actually hurting the batter significantly. Interestingly enough, The Book seems to indicate that on the whole, a baserunner at first with less than two outs helps the batter... but the faster the runner on first, the worse the batter does.