Ausmus reported to Comerica Park with the knowledge his mother had passed away overnight at his parents' home in Connecticut. Cause of death and other details were not immediately known.
Lamont managed one game recently while Ausmus was serving a one-game suspension for an in-game outburst directed toward an umpire. Ausmus took off his sweatshirt and covered home plate with it.
"I'll be managing (Wednesday) and Friday," Lamont said. "I was going to be the acting manager Friday anyway because Brad's daughter is graduating (from high school in San Diego, his offseason home)."
The Tigers were arranging a flight from Detroit to Connecticut for Ausmus prior to Wednesday's game.