Karim Benzema looks set to join Luka Modric and Gareth Bale on the sidelines for Real Madrid's decisive Champions League quarter-final, second leg clash with Atletico Madrid on Wednesday with a knee problem.

"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 on Tuesday.

Madrid did not add how long the French international will be out of action, but Spanish media reported he has been ruled out of the return against Atletico.

Benzema suffered the injury during last week's 0-0 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.