On January 9, 1975, Brookens was drafted by the Detroit Tigers in the first round of the 1975 MLB draft. In 12 MLB seasons, Brookens played 1,065 games at third base, 162 games at second base, and 119 games at shortstop. Tigers radio announcer Ernie Harwell nicknamed Brookens "the Pennsylvania Poker", a play on the song "Pennsylvania Polka". Brookens batted.246 in his 12-year career, with 71 home runs and 431 runs batted in in 1,336 games. His range factor was well above league average. He did lead American Leaguethird basemen in errors twice, in 1980 and 1985, but that was largely because he was getting to so many more grounders than other fielders; his range factor, which measures the number of plays a fielder makes, was consistently above league average. Brookens also has the dubious honor of sharing the AL record for the most errors in a game by a third baseman, four, on September 6, 1980. Traditionally an infielder, Brookens found himself behind the plate in a game against the Texas Rangers on July 20, 1985. With regular catcher Lance Parrish hurt and Bob Melvin and Marty Castillo removed from the game in favor of pinch-hitters, Brookens filled the role and wound up catching five innings before Detroit finally won the game. On August 20, 1980, Brookens went 5-for-5 with a triple and a home run, and also started a triple play in an 8–6 win over the Milwaukee Brewers. On September 18, 1984, Brookens hit an eighth inning solo home run into the left field seats at Tiger Stadium off of Milwaukee Brewers lefty Mike Caldwell on a 3-2 fastball. This was the clinching game leading the Tigers toward their 1984 World Championship. Besides, Brookens played winter baseball with the Leones del Caracas club of the Venezuelan League during the 1977–1979 seasons. He won a World Series ring with the Tigers in 1984.
As a manager
Brookens in 2005 and 2006 was the manager of the Class A New York–Penn LeagueOneonta Tigers in the Detroit Tigers minor league system. In 2007, Brookens was hired to lead the West Michigan Whitecaps which won the championship of the Class A – Midwest League that year. After winning a championship with the Whitecaps, the Tigers promoted Brookens again in 2008, this time to the Erie SeaWolves, their Class AA – Eastern League affiliate.
As a coach
On November 9, 2009 the Tigers hired Brookens as their new first base coach. The move reunited Brookens with Tigers manager Jim Leyland, who had managed Brookens in the minor leagues in the 1970s. In 2013, Brookens was moved across the diamond to serve as the Tigers third base coach; he was mentioned as a possible future manager of the club when Leyland retired, but former catcher Brad Ausmus was named Leyland's replacement. Leyland selected Brookens to serve as bench coach for Team USA during the 2017 World Baseball Classic, coaching on a staff that included pitching coachJeff Jones and first base coach Alan Trammell, as teammate of Brookens from 1979 to 1988.
Family
Brookens' twin brother Tim was also drafted in 1975 by the Texas Rangers; he was later traded to the Tigers organization, but never made the majors. In spring training, Tim and Tom would sometimes switch identities, even suiting up in each other's uniforms; Tim is believed to have played at least one exhibition game disguised as Tom. Their cousin, Ike Brookens, pitched for the Tigers in 1975, while Ike's son Casey Brookens also played in the minors in the 1990s before retiring to become a high school coach in Pennsylvania.
