I received this error when retrieving data for the 2012 regular season. When I change the line of code in getData(...) from,
out <- dplyr::bind_rows(ds.list)
to
out <- do.call(rbind, lapply(ds.list, data.frame, stringsAsFactors=FALSE))
the code completes without an error, though balls and strikes are of type character so they need to be converted to integer: out <- transform(out, balls = as.integer(balls), strikes = as.integer(strikes))