Earned run average in the context of "Blake Snell"

In baseball, an earned run is any run that was fully enabled by the offensive team's production in the face of competent play from the defensive team. Conversely, an unearned run is a run that would not have been scored without the aid of an error or a passed ball committed by the defense; it is "unearned" in that it was, in a sense, "given away" by the defensive team.

Earned and unearned runs count equally toward the game score; the difference is purely statistical. Both total runs and earned runs are tabulated as part of a pitcher's statistics, but earned runs are specially denoted because of their use in calculating a pitcher's earned run average (ERA), the number of earned runs allowed by the pitcher per nine innings pitched (i.e., averaged over a regulation game). Thus, in effect, the pitcher is held personally accountable for earned runs, while the responsibility for unearned runs is shared with the rest of the team.