Rui Costa and Nuno Assis have been ruled out of Benfica's UEFA Champions League match with Manchester United on Tuesday.
The clubs go head-to-head in the second match of Group F with United anxious to avenge last season's exit from the competition at the hands of the same opponents.
The Estadio da Luz side have been boosted by the recovery of centre back Ricardo Rocha, but will be without their experienced pair of attacking midfielders.
Coach Fernando Santos has Kostas Katsouranis, Georgios Karagounis and Armando Petit (pictured) at his disposal as replacements, but could also opt to change his system.
FC Copenhagen held the Portuguese outfit to a disappointing 0-0 draw in their opening match, so the fixture has taken on added importance.