From @Only-Slightly-Bent (Only-Slightly-Bent) with much appreciated PR (which I will close since I addressed it on the development branch before reading yours):
Looks like in the most recent version of R there is an error in the most_recent_mlb_season() function. It throws the following error: Error in substr(Sys.Date(), 1, 4) - 1 :
non-numeric argument to binary operator.
Moving the parenthesis fixes it so that you cast the string as a double before subtracting instead.
From @Only-Slightly-Bent (Only-Slightly-Bent) with much appreciated PR (which I will close since I addressed it on the development branch before reading yours):