The 33-year-old attacker was taken off on the hour mark during the 3-2 loss to Portugal on Wednesday evening with a suspected hamstring problem.
Veteran Dennis Rommedahl may have played his 118th and last international on Wednesday after picking up an injury in the second half of the Portugal game.
Tobias Mikkelsen is expected to come into the side and from what we saw from him against the Seleccao he will be an able replacement.
The Germans do not know Mikkelsen and this could be an advantage for the Danes.
Niki Zimling, who has been nursing a toe injury since the tournament began, could be fit to play, however.
"There is no chance with Rommedahl. Zimling I can still hope for," Olsen told reporters.
The severity of the Brondby forward's injury remains unknown for now as he will undergo further tests to determine the length of his recovery, and whether he can continue in the championship should the Danes advance to the knockout phase.
Denmark will seal progression to the quarter-finals if they beat Germany and Portugal fail to pick up three points against Netherlands.
Kick-off for both clashes on June 17 is at 20:45CET.