The 54-year-old Fidrych, who captured the imagination of the country during his rookie of the year season in 1976, died Monday in an accident at his Massachusetts home.
Authorities are awaiting autopsy results to determine how he died.
The Fidrych tribute took place after the previously scheduled events honoring Jackie Robinson.
Because every player wore No. 42 in honor of Robinson, Fidrych's No. 20, normally worn by backup catcher Matt Treanor, went unused.
A funeral for Fidrych was scheduled for Friday at First Parish Unitarian Church in Northborough, Mass.