"One of the key issues over buying Robinho has always been that Real Madrid are looking for a replacement," Kenyon told the Blues' official website.
"It is fair to say that is what has been holding up discussions between the two clubs. It has not progressed over the last couple of days but the window is open until the end of August and there's still plenty of time to run."
Kenyon also insisted Didier Drogba, who is currently recovering from a knee injury and has been linked with Real Madrid, will not be sold and played down talk of a move for Werder Bremen playmaker Diego.
"I think there is absolutely no question that any deal will be done with regard to Didier Drogba," Kenyon added. "Didier is in rehab and will continue to be a Chelsea player. We can squash that one.
"With regard to Diego, I was (as) amazed as everybody else to read it in the newspapers this morning, so again, I think that's just pure speculation."