The 2015 club held the major leagues ' best run - differential at + 95 .
Their staff ERA ( 2.63 ) was the lowest through 74 games in a season since the Baltimore Orioles in 1972 ( 2.31 ) .
The 2015 club held the major leagues ' best run - differential at + 95 , and their staff ERA ( 2.63 ) was the lowest through 74 games in a season since the Baltimore Orioles in 1972 ( 2.31 ) .