The 31-year-old only joined the Italian club in July and is yet to make an appearance for the Rossoneri.
Strinic has been a Croatian senior international since May 2010, earning 49 caps for his country. He was part of the Croatia team that reached the World Cup final in Russia this summer, starting in six of the seven matches in the tournament.
According to his club Milan, the player must "suspend temporarily all competitive sporting activity," after he was found to have the heart condition.
The heart problem was reportedly found during a routine check, with the Italian side reporting that
Milan announce that Strinic suffers from an initial hypertrophy of the heart muscle. Therefore the player will have to temporarily suspend competitive sport activity until the tests are completed.— TheMilanBible (@TheMilanBible) August 18, 2018
FORZA STRINIC! pic.twitter.com/cxydrUqQ5v
After one year at the Genoa club he made the move to Milan on a free transfer this summer.