The Turkish midfielder appeared to be on his way out of the Liga champions this summer, but may still have a future at the club, albeit in a defensive position
The midfielder has featured in defence on a number of occasions during pre-season, acting as cover for Marcelo, who is away on international duty with Brazil's Olympic team, and the Blancos are pleased with the Turkey international's performance at the back.
"The important thing for Nuri at this point is to play. He has been playing wing-back and is doing well. He is happy to play in any position," Karanka was quoted as saying on the club's official website.
"We only have Fabio Coentrao on the left side at the moment. He is playing very well, but Nuri is also ready to step up.
"The important thing is that there are no injuries. Those who play during pre-season are helping out the team."
Sahin, 23, has been heavily linked with a move to Arsenal, while Tottenham Hotspur are also understood to be keen on the midfielder.
Nevertheless, a departure from the Santiago Bernabeu no longer seems a given if Karanka's latest comments are to be believed.