Denmark’s assistant coach Jon Dahl Tomasson says that William Kvist could feature in Sunday’s game.
The midfielder punctured a lung and broke two ribs in Denmark’s opening match against Peru on 16 June.
Winger Yussuf Poulsen is available after serving a one-game ban against France.
Neither of these teams has conceded from open play yet at this World Cup, with the solitary goal allowed by both sides coming from the penalty spot.
While the Danes rode their luck at times in Group C, particularly in the opening win against wasteful Peru, Croatia have been one of the most impressive teams in Russia.
They won all three games in Group D, including a comprehensive 3-0 win against Argentina and a 2-1 victory versus Iceland which was achieved despite making nine changes.
Like Croatia, Denmark are hoping to reach the quarter-finals for only the second time in their history.
Their defensive approach in the draw against France in their final group game divided opinion, but coach Age Hareide was unrepentant, pointing out that they couldn’t rely on already eliminated Peru to get a result against Australia.
Round of 16 : 7/1,
1 July : 2018
12:00 : Am