Going by strictly win-loss percentage, the 1978 season is the worst season in franchise history since 1961. That year, the team went 69-93, finished 5th in the division (the Mets finished last), and were 21 games behind the Phillies for first place. The team finished nearly .040 points behind its Pythagorean win-loss (record based on run differential) and had one of the lowest attendance rates of the decade (1,278,215 attendees).
The season did not start off well, as the team fired its manager, Vern Rapp, after only 28 games. He had a 7-11 record. Jack Krol was the interim manager for only two games, and Ken Boyer finished the season as manager, going 61-81 and finishing the season. Another lowlight from the season would be Tom Seaver's no-hitter against the Cardinals on June 16th. Perhaps the worst aspect of the season would be its individual performances. Only one player in the entire team was recognized with an award: Keith Hernandez won a Gold Glove. No other players received an award of any kind that year.
The Cardinals ranked 21st in the majors in batting average, grounded into the 8th most double plays, and had the 24th-worst OPS+ that year. The league had only 26 teams at this time. On the pitching side, the team was about average in all major categories: 17th in ERA+, 12th in ERA, 23rd in home runs allowed, and 5th in strikeouts.
Teams such as the Cubs (3-15 against), Giants (3-9 against), and Padres (3-9 against) all had the Cardinals' number that particular year. Despite big-name players such as Lou Brock, Keith Hernandez, Ted Simmons, Gary Templeton, and Bob Forsch, the 1978 Cardinals played terribly. This season presented the worst win-loss percentage since 1894, and the team struggled to make it back to the postseason for a few more years.