Now the Brewers are bringing Coles back. He will be tasked with correcting an offense that mostly disappeared during the second half of the 2014 season, leading to hitting coach Johnny Narron's dismissal.
"It's tough leaving a great organization like the Tigers," Coles said. "I was content and loved my job working with some of the best hitters in baseball -- in Miguel Cabrera's case, the best hitter in baseball. It was a great experience. It's sad to leave, but you get an opportunity to get one of 30 jobs in the game, and a great group of hitters."
After running second among National League clubs to the high-altitude Rockies in every major offensive category during the first three months of the season, the Brewers struggled to score from July onward. They fell from averaging 4.56 runs per game in the first three months to 3.42 runs per game in the final three. Among the 30 Major League teams, only the Reds struggled more to score down the stretch.
Coles, who wishes to manage in the Major Leagues someday, was tremendously popular among players during his previous tenure in Milwaukee's organization. He will face a short learning curve with many hitters, including three young players -- second baseman Scooter Gennett, shortstop Jean Segura and outfielder Khris Davis -- whom the Brewers believe can improve on pitch selection and production. Coles managed all three (Segura only briefly) at the Double-A level in 2012.
Coles worked closely with other Brewers mainstays during big league Spring Training camp during his initial time with Milwaukee. He and other Minor League instructors would work in big league camp until the Minor League program began in earnest in March.
"You're intertwined with all the guys. It's a smooth transition," Coles said. "I know them, they know me. There's high expectations. It's a great hitting team, so you're not trying to reinvent the wheel, but you try to put every hitter in the best possible position to be successful."
Coles didn't have to do an overhaul with the Tigers, given the talent in their lineup. What he brought, however, was a boundless amount of positive energy and a steady source of constructive critiques in support of primary hitting coach Wally Joyner.
"Great energy and detail-oriented," Ausmus said of Coles.
Despite losing Prince Fielder from the middle of the lineup, the Tigers led the Majors in batting average and RBIs, topped the American League in OPS and finished second in the big leagues in runs scored. Beyond the big names of Cabrera, Victor Martinez, Ian Kinsler and Torii Hunter, Coles worked with J.D. Martinez during his sudden rise from a Spring Training cut by Houston to a middle-of-the-order impact hitter for Detroit and helped keep Nick Castellanos focused during the ups and downs of his rookie season.
"Darnell did a great job in working with Wally and our hitters," Tigers president and general manager Dave Dombrowski said. "Knowledgeable and hard working. He is ready to become the main hitting coach for a Major League team."
Coles said he'll take the lessons he learned with him to Milwaukee.
"You watch how those guys work and prepare, and you get an understanding how those guys are as good as they are," he said. "It's a great group of hitters, a great group of guys, and you take that knowledge with you as you move on."
As a player, Coles spent parts of 14 seasons with the Mariners, Tigers, Pirates, Blue Jays, Rockies, Giants, Cardinals and Reds, mostly as a third baseman and outfielder. His claim to fame is that he is one of only 14 players, including Babe Ruth, to post three-homer games in both the American and National leagues.
The Brewers have one vacancy remaining on their staff, having dismissed first-base coach Garth Iorg along with Narron earlier this month.