The reigning champions thumped Cornella 4-1 in the first leg of their round of 32 tie last month and should have few problems against the Catalan minnows as they look to reach the final 16, although Madrid coach Carlo Ancelotti may have to tinker with his line-up.
Reports in the Spanish media suggest Kroos will be given a rest at The Santiago Bernabeu, while Benzema was replaced with 17 minutes remaining in Madrid's record-breaking 2-1 win over Malaga on Saturday.
The victory was Madrid's 16th in a row in all competitions - setting a new club record winning streak.
"He [Benzema] suffered a blow to his leg and was troubled a little bit. That's why I took him off," Ancelotti said after the match.
Cornella sit 12th in Segunda B in Spain and have not won in six matches in all competitions, including a 6-2 thumping at Atletico Baleares in the league on Saturday.
In the first leg, Raphael Varane scored twice for Madrid - either side of Oscar Munoz's goal for Cornella - before Javier Hernandez and Marcelo struck in the second half for the capital club to wrap up the victory.
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