As reported earlier this week on skysports.com, The Gers' interest in Boutahar became known after assistant manager Jan Wouters spotted him in action.
The 22-year-old is set to be available on a free transfer in the summer and Rangers look very much in contention for his signature.
RKC's technical director Marcel Brands has now admitted that they are aware of the Scottish champions' interest in him.
"I have heard of Rangers' interest in him and there is nothing we can do to stop it," Brands told The Herald.
"We have been honest with our players because there is going to be a management change in the summer.
"There is a period of uncertainty and we have asked those out of contract to be patient, but Said has already told us he intends to leave.
"If he goes to Rangers, it will be a good move for him because they are a much bigger club than us and I know how much he wants to play for the Dutch national team."
Meanwhile, young defender Alan Hutton has signed a new long-term contract with the club.
The 19-year-old has just made the breakthrough into the first team at Ibrox and he grabbed his first goal for the club on Tuesday against Dunfermline.
He has now pledged his future to The Gers until 2007 after manager Alex McLeish handed him a new deal.
"I'm absolutely delighted to have signed a new deal and it's great to know I'm tied to the club for the next three years," he told Rangers News.
"I'm so happy, it's been a fantastic week. I can now just concentrate on my football and, hopefully, show the manager what I am capable of.
"I've been desperate to get my chance and now I've been given it, I have to make sure I take it.
"It was always in my mind to stay here because the club has been my life for so long now.
"I've grown up at Rangers and this is really the only club for me, so I'm delighted."
