Gary from California asks:
In the Cleveland - Toronto game that went 19 innings, Toronto brought in a position player to pitch in the top of the 19th, Darwin Barney, who had never pitched before. He gave up a home run to the first batter he faced. Had he been pulled after the first batter, what would have been his ERA since he would have only faced one batter who scored and got no outs?
ERA is calculated by the formula ERA=9*(Earned Runs/Innings Pitched). Since Barney would have had an Innings Pitched total of 0, his ERA would be resembled as "infinite" (∞) since it is impossible to divide by 0 and he, in theory, has given up an infinite amount of runs per 9 innings since he never recorded an out.
Answered by: Jonathan Bravo