Rangnick would be prepared to let the 34-year-old go if he was unhappy, but he has not had any complaints from the Spaniard, who has one year left on his current contract.
"In terms of Raul it is the same as it is with all of the players of my squad. If he comes up saying he wants to move on we'll look into things," commented Rangnick to BILD.
"So far he hasn't said anything to me and we've not received any enquiries from any club.
"I have been speaking to Raul over the past months every now and then and he has said everything is fine.
"Raul is definitely an important player for our team, although there are eleven players on the pitch."