Real Madrid No2 Karanka: Nuri Sahin must stay
Sahin has been linked with a loan return to Borussia Dortmund.
After victory over Real Zaragoza, Karanka said: "It was a match for Nuri, but we decided to use Lass. There are many games left and Nuri is working very well. He will be very good for us. We give him our support. All he needs is more playing time."