Answered January 12th, 2020

Ray Collins has the lowest ERA by a Red Sox left-hander with 100.0+ innings pitched at home in a season, with an ERA of 0.08 in 1911.

lowest era in a season by a red sox lhp with 100 ip at home
Interpreted as:
lowest era in a season by a red sox lhp with 100 or more ip at home

See Trending MLB Searches