In 1970, and despite being demoted to Toledo for 26 days early in the season, Timmermann finished third in the American League with 27 saves and sixth in the league with 43 games finished. He appeared in 61 games, all as a relief specialist, breaking the Detroit franchise record of 55 pitching appearances set by Larry Sherry in 1966. Timmermann compiled a record of 6–7 with a 4.11 ERA. He was credited with converting a bullpen that manager Mayo Smith had called "the worst I've ever seen in baseball" into one that became "almost unbeatable." In one sequence of 11 games in June and July, Timmermann recorded nine saves and two wins. At the end of the 1970 season, Timmermann was voted "Tiger of the Year" by the Detroit chapter of the Baseball Writers' Association of America — garnering 25% of the votes to edge Mickey Stanley and Al Kaline. In November 1970, veteran Detroit sports writer Watson Spoelstra called Timmermann's 1970 performance "the strongest bullpen job ever achieved in Detroit."