He is going on the 10-day disabled list.
The 38-year-old left Thursday's game against the Tampa Bay Rays and spent the evening in the hospital as a result of the heart condition.
Detroit has four games in Seattle beginning Monday followed by three games in San Diego before returning home.
Ausmus said on the radio that whatever was ailing Martinez, presumably a virus, was "more scary than a general baseball injury". "It's not something that, at his age, you generally consider an issue or worry about".
Martinez has just five home runs this season, remarkably low numbers for a cleanup hitter. Along with placing Martinez on the DL, the team also called up catcher/first baseman John Hicks from Triple-A Toledo. He's under contract with the Tigers through the end of the 2018 season.