Sisler had been relieved of duties after the Reds 1965 season when the Reds finished the season 89-73. Sisler was interim manager in 1964, subbing for popular manager Fred Hutchinson who was stricken with cancer. The Reds wasted a late season nine-game winning streak that moved them into first place with four games remaining before losing four of the last five games and costing them the pennant. Sisler was named manager in the offseason after Hutchinson had resigned before passing away in December. Sisler’s 1965 team was three games out of first place with ten games to play before losing seven of it’s last eight games to fall out of contention and finish in fourth place. Sisler’s record in 1+ seasons with the Reds was 121-94. The two late season swoons cost Sisler his management position.
Heffner had 12 years of minor league management experience, including two with the Reds AAA San Diego franchise and had played for Reds General Manager Bill DeWitt while with the St. Louis Browns. About six weeks after being Reds manager, the Reds and DeWitt asked Heffner to manage with one hand tied behind his back as they traded Reds star Hall of Fame outfielder Frank Robinson to the Baltimore Orioles. The Reds lost seven of their first eight games to start the season. In a season of streaks, they rallied to get back above .500 at 19-18, fell to 26-34, and then won eight games in a row to get back to .500 again at 34-34. However, a ten-game losing streak dropping the Reds to 36-46 was enough for DeWitt, who replaced Heffner with Dave Bristol while the Reds were 37-46.
The Reds offense was missing Robinson and dropped by nearly one run per game in 1966 and this missing offense maligned Heffner and Bristol all season. Meanwhile, Robinson was busy winning the Triple Crown and the American League Most Valuable Player Award playing for the Orioles. The Reds had been grooming Bristol, a catcher, to be a manager since age 23 when he started managing and coaching in the Reds system since 1957. He was only 33-years-old when he started managing the Reds. The Reds played at a 39-38 clip for Bristol to close the season. The 1966 season was the only losing season for the Reds from 1961 through 1970. Bristol would manage the Reds through the 1969 season (298-265) before giving way to Sparky Anderson.