Campbell, the New Orleans Saints’ assistant head coach, will interview with Detroit today.
Smith, the Tennessee Titans’ offensive coordinator, will interview on Tuesday.
Detroit has also spoken with former Bengals head coach Marvin Lewis, Chiefs offensive coordinator Eric Bieniemy, Lions interim head coach Darrell Bevell and 49ers defensive coordinator Robert Saleh.
The club also reportedly requested to interview Todd Bowles, the Buccaneers defensive coordinator and former head coach of the New York Jets.
Detroit’s pool of known candidates for the general manager position has climbed to 11: Former Falcons general manager Thomas Dimitroff, former Texans general manager Rick Smith, former Chiefs general manager Scott Pioli, ESPN analyst Louis Riddick, Saints assistant general manager for pro personnel Terry Fontenot, Rams college scouting director Brad Holmes, Vikings assistant general manager George Paton, Saints assistant general manager Jeff Ireland and internal candidates Rob Lohman, Lance Newmark and Kyle O’Brien.