A knee problem prevented Benzema travelling with the Spanish champions to Deportivo La Coruna on Saturday as they look to make up ground on Barca and Atletico Madrid in the Primera Liga.
Jose Mourinho's men visit Camp Nou in the Copa del Rey in midweek with the tie finely balanced at 1-1 and Benzema hopes to make the second leg clash.
The striker, who has scored nine goals in all competitions for Real this season, knows his injury comes at a crucial time for the club.
"I am working hard and with a lot of hope to rejoin the team as soon as possible in this crucial week," he told the club's official website.
"I am very sorry to have not been able to be in La Coruna. My team-mates and manager know that I am working hard to arrive in the best condition as quickly as possible.
"My sensations right now are positive and nothing makes me more excited than being in good shape to be able to help my team as soon as possible."