The France international joins Luka Modric and Gareth Bale on the sidelines for Los Blancos’ decisive second leg clash at the Santiago Bernabeu??with a knee problem.
As well as the injury absences, attacking full-back Marcelo is suspended for the decider with the tie standing at 0-0 from the first game.
“After the tests carried out on Karim Benzema by the Real Madrid medical team, they have diagnosed a sprain in the medial collateral ligament in his right knee,” the club said in a statement.
Benzema suffered the injury during last week’s goalless draw in the first leg between the sides and subsequently sat out Saturday’s 3-1 win over Malaga.
Modric also suffered a knee ligament sprain against Malaga, but Benzema’s injury is not expected to be as serious as the Croatian’s, who will miss the rest of the season unless Madrid make it to the Champions League final on June 6.
Bale pulled up after less than five minutes against Malaga with a calf injury that is expected to keep him out for up to three weeks.