n.(baseball) a measure of a pitcher's effectiveness; calculated as the average number of earned runs allowed by the pitcher for every nine innings pitched
He picked up 54 points on our scorecard that year by, among other stats, going 21-7 for a 76-86 team and for posting a 2.05 earned-run average that was more than two full runs per game lower than the American League average (among pitchers with at least 150 innings).