Ellis struggled for the remainder of the 1970 season, and finished the year with a 13–10 win-loss record as he experienced elbow and shoulder pain. However, he finished second in the NL with four shutouts and seventh with a 3.21 ERA. The Pirates won the National League (NL) East division championship. Ellis started Game 1 of the 1970 National League Championship Series (NLCS) to the Cincinnati Reds. Ellis took the loss, and the Pirates lost the series to the Reds in three games.