In June 2012, Harrah joined the Detroit Tigers major league coaching staff in an unofficial capacity. Tigers manager Jim Leyland noted that with so many players struggling at once, hitting coach Lloyd McClendon had been stretched thin. The notion of two hitting coaches had been recommended to Leyland by friend and former colleague Tony La Russa. LaRussa had been the first to adopt a two-coach system when he named an assistant hitting coach, (Mike Aldrete), with the St. Louis Cardinals in 2008. In the month following Harrah's arrival, the Tigers offense increased their average runs per game from 4.3 to 5.6.