Ronaldo will miss Wednesday's King's Cup final against Barcelona after failing to recover from knee and thigh muscle problems.
Real and Barcelona meet King's Cup final in Valencia in the latest edition of the 'Clasico' between the world's two richest clubs by income.
Barcelona compounded their exit from the Champions League by losing 1-0 at Granada, letting Real move ahead into second place with a 4-0 win over Almeria.
Real Madrid coach Carlo Ancelotti has not ruled Cristiano Ronaldo out of the Copa del Rey final just yet, despite injury concerns.
Borussia Dortmund will make use of an option to buy on-loan midfielder Sahin from Real, making his return to last season's Champions League runners-up permanent.
The first legs will be played on April 22 and 23, with the return matches on April 29 and 30.
Real Madrid forward Ronaldo is likely to miss Wednesday's Copa del Rey final against Barcelona due to a leg injury.
The Germans outran their opponents, hit the woodwork twice and have only themselves to blame for not adding at least one more goal to their tally.
Real Madrid reached the semi-finals of the Champions League on Tuesday despite losing 2-0 (3-2 aggregate) at Borussia Dortmund in their second leg match.
The Portuguese international sat out the weekend La Liga match with Real Sociedad after leaving last week's first leg against Dortmund with an injury.
Madrid hold a 3-0 lead from the first leg and the nine-time champion have never lost a Champions League tie after winning the opening leg by that score.